21551996 has 6 divisors (see below), whose sum is σ = 37716000. Its totient is φ = 10775996.

The previous prime is 21551993. The next prime is 21552007. The reversal of 21551996 is 69915512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21551993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2693996 + ... + 2694003.

It is an arithmetic number, because the mean of its divisors is an integer number (6286000).

Almost surely, 2^21551996 is an apocalyptic number.

It is an amenable number.

21551996 is a deficient number, since it is larger than the sum of its proper divisors (16164004).

21551996 is a wasteful number, since it uses less digits than its factorization.

21551996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5388003 (or 5388001 counting only the distinct ones).

The product of its digits is 24300, while the sum is 38.

The square root of 21551996 is about 4642.4127347749. The cubic root of 21551996 is about 278.2888669647.

The spelling of 21551996 in words is "twenty-one million, five hundred fifty-one thousand, nine hundred ninety-six".