21018064860 has 144 divisors (see below), whose sum is σ = 72272796960. Its totient is φ = 4901368320.

The previous prime is 21018064849. The next prime is 21018064867. The reversal of 21018064860 is 6846081012.

21018064860 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 8 + 0 + 648 + 6 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21018064867) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 191911 + ... + 280830.

Almost surely, 2^21018064860 is an apocalyptic number.

21018064860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21018064860 is an abundant number, since it is smaller than the sum of its proper divisors (51254732100).

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

21018064860 is a wasteful number, since it uses less digits than its factorization.

21018064860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 472788 (or 472783 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The spelling of 21018064860 in words is "twenty-one billion, eighteen million, sixty-four thousand, eight hundred sixty".