21486816 has 96 divisors (see below), whose sum is σ = 67525920. Its totient is φ = 6607872.

The previous prime is 21486811. The next prime is 21486821. The reversal of 21486816 is 61868412.

It is an interprime number because it is at equal distance from previous prime (21486811) and next prime (21486821).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21486811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10276 + ... + 12188.

It is an arithmetic number, because the mean of its divisors is an integer number (703395).

Almost surely, 2^21486816 is an apocalyptic number.

21486816 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21486816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33762960).

21486816 is an abundant number, since it is smaller than the sum of its proper divisors (46039104).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21486816 is a wasteful number, since it uses less digits than its factorization.

21486816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1945 (or 1931 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 21486816 is about 4635.3873624542. The cubic root of 21486816 is about 278.0080393790.

The spelling of 21486816 in words is "twenty-one million, four hundred eighty-six thousand, eight hundred sixteen".