21156646245 has 64 divisors (see below), whose sum is σ = 39124836864. Its totient is φ = 9562291200.

The previous prime is 21156646193. The next prime is 21156646249. The reversal of 21156646245 is 54264665112.

It is not a de Polignac number, because 21156646245 - 2¹³ = 21156638053 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21156646197 and 21156646206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21156646249) 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 in 63 ways as a sum of consecutive naturals, for example, 14559939 + ... + 14561391.

It is an arithmetic number, because the mean of its divisors is an integer number (611325576).

Almost surely, 2^21156646245 is an apocalyptic number.

It is an amenable number.

21156646245 is a deficient number, since it is larger than the sum of its proper divisors (17968190619).

21156646245 is a wasteful number, since it uses less digits than its factorization.

21156646245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2942.

The product of its digits is 345600, while the sum is 42.

The spelling of 21156646245 in words is "twenty-one billion, one hundred fifty-six million, six hundred forty-six thousand, two hundred forty-five".