21371628 has 12 divisors (see below), whose sum is σ = 49867160. Its totient is φ = 7123872.

The previous prime is 21371627. The next prime is 21371653. The reversal of 21371628 is 82617312.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 21371595 and 21371604.

It is not an unprimeable number, because it can be changed into a prime (21371627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 890473 + ... + 890496.

Almost surely, 2^21371628 is an apocalyptic number.

It is an amenable number.

21371628 is an abundant number, since it is smaller than the sum of its proper divisors (28495532).

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

21371628 is a wasteful number, since it uses less digits than its factorization.

21371628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1780976 (or 1780974 counting only the distinct ones).

The product of its digits is 4032, while the sum is 30.

The square root of 21371628 is about 4622.9458140887. The cubic root of 21371628 is about 277.5103607851.

The spelling of 21371628 in words is "twenty-one million, three hundred seventy-one thousand, six hundred twenty-eight".