21207996 has 18 divisors (see below), whose sum is σ = 53609192. Its totient is φ = 7069320.

The previous prime is 21207881. The next prime is 21207997. The reversal of 21207996 is 69970212.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 589111 = 21207996 / (2 + 1 + 2 + 0 + 7 + 9 + 9 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 21207996.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21207997) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 294520 + ... + 294591.

Almost surely, 2^21207996 is an apocalyptic number.

It is an amenable number.

21207996 is an abundant number, since it is smaller than the sum of its proper divisors (32401196).

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

21207996 is a wasteful number, since it uses less digits than its factorization.

21207996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 589121 (or 589116 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 21207996 is about 4605.2140015422. The cubic root of 21207996 is about 276.8002922191.

The spelling of 21207996 in words is "twenty-one million, two hundred seven thousand, nine hundred ninety-six".