21991202 has 4 divisors (see below), whose sum is σ = 32986806. Its totient is φ = 10995600.

The previous prime is 21991199. The next prime is 21991219. The reversal of 21991202 is 20219912.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19971961 + 2019241 = 4469^2 + 1421^2 .

It is a super-2 number, since 2×21991202² = 967225930809608, which contains 22 as substring.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5497799 + ... + 5497802.

Almost surely, 2^21991202 is an apocalyptic number.

21991202 is a deficient number, since it is larger than the sum of its proper divisors (10995604).

21991202 is a wasteful number, since it uses less digits than its factorization.

21991202 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10995603.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 21991202 is about 4689.4777960877. The cubic root of 21991202 is about 280.1665760519.

The spelling of 21991202 in words is "twenty-one million, nine hundred ninety-one thousand, two hundred two".