21111656364 has 18 divisors (see below), whose sum is σ = 53365575900. Its totient is φ = 7037218776.

The previous prime is 21111656353. The next prime is 21111656399. The reversal of 21111656364 is 46365611112.

21111656364 is a `hidden beast` number, since 2 + 1 + 1 + 1 + 16 + 5 + 636 + 4 = 666.

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: 586434899 = 21111656364 / (2 + 1 + 1 + 1 + 1 + 6 + 5 + 6 + 3 + 6 + 4).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 293217414 + ... + 293217485.

Almost surely, 2^21111656364 is an apocalyptic number.

It is an amenable number.

21111656364 is an abundant number, since it is smaller than the sum of its proper divisors (32253919536).

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

21111656364 is a wasteful number, since it uses less digits than its factorization.

21111656364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586434909 (or 586434904 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The spelling of 21111656364 in words is "twenty-one billion, one hundred eleven million, six hundred fifty-six thousand, three hundred sixty-four".