21887620 has 48 divisors (see below), whose sum is σ = 48787200. Its totient is φ = 8225280.

The previous prime is 21887617. The next prime is 21887623. The reversal of 21887620 is 2678812.

It is an interprime number because it is at equal distance from previous prime (21887617) and next prime (21887623).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21887623) 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, 90700 + ... + 90940.

It is an arithmetic number, because the mean of its divisors is an integer number (1016400).

Almost surely, 2^21887620 is an apocalyptic number.

21887620 is a gapful number since it is divisible by the number (20) 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 21887620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24393600).

21887620 is an abundant number, since it is smaller than the sum of its proper divisors (26899580).

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

21887620 is a wasteful number, since it uses less digits than its factorization.

21887620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508 (or 506 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 21887620 is about 4678.4206736889. The cubic root of 21887620 is about 279.7260074837.

The spelling of 21887620 in words is "twenty-one million, eight hundred eighty-seven thousand, six hundred twenty".