21401886 has 32 divisors (see below), whose sum is σ = 47190528. Its totient is φ = 6416640.

The previous prime is 21401881. The next prime is 21401903. The reversal of 21401886 is 68810412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21401881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4731 + ... + 8073.

It is an arithmetic number, because the mean of its divisors is an integer number (1474704).

Almost surely, 2^21401886 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21401886, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23595264).

21401886 is an abundant number, since it is smaller than the sum of its proper divisors (25788642).

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

21401886 is a wasteful number, since it uses less digits than its factorization.

21401886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3456.

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 21401886 is about 4626.2172452231. The cubic root of 21401886 is about 277.6412656281.

The spelling of 21401886 in words is "twenty-one million, four hundred one thousand, eight hundred eighty-six".