21628156 has 48 divisors (see below), whose sum is σ = 44593920. Its totient is φ = 9072000.

The previous prime is 21628153. The next prime is 21628169. The reversal of 21628156 is 65182612.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21628151) 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, 33961 + ... + 34591.

It is an arithmetic number, because the mean of its divisors is an integer number (929040).

Almost surely, 2^21628156 is an apocalyptic number.

It is an amenable number.

21628156 is an abundant number, since it is smaller than the sum of its proper divisors (22965764).

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

21628156 is a wasteful number, since it uses less digits than its factorization.

21628156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 706 (or 704 counting only the distinct ones).

The product of its digits is 5760, while the sum is 31.

The square root of 21628156 is about 4650.6081322769. The cubic root of 21628156 is about 278.6162854161.

The spelling of 21628156 in words is "twenty-one million, six hundred twenty-eight thousand, one hundred fifty-six".