21642007204 has 6 divisors (see below), whose sum is σ = 37873512614. Its totient is φ = 10821003600.

The previous prime is 21642007193. The next prime is 21642007207. The reversal of 21642007204 is 40270024612.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 15140810304 + 6501196900 = 123048^2 + 80630^2 .

It is not an unprimeable number, because it can be changed into a prime (21642007207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2705250897 + ... + 2705250904.

Almost surely, 2^21642007204 is an apocalyptic number.

It is an amenable number.

21642007204 is a deficient number, since it is larger than the sum of its proper divisors (16231505410).

21642007204 is a wasteful number, since it uses less digits than its factorization.

21642007204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5410501805 (or 5410501803 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 28.

The spelling of 21642007204 in words is "twenty-one billion, six hundred forty-two million, seven thousand, two hundred four".