21146156640 has 144 divisors (see below), whose sum is σ = 82470050208. Its totient is φ = 4833404928.

The previous prime is 21146156627. The next prime is 21146156653. The reversal of 21146156640 is 4665164112.

21146156640 is a `hidden beast` number, since 2 + 1 + 1 + 4 + 6 + 1 + 5 + 6 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (21146156627) and next prime (21146156653).

It is a tau number, because it is divible by the number of its divisors (144).

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

It is a junction number, because it is equal to n+sod(n) for n = 21146156595 and 21146156604.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 1038837 + ... + 1058996.

It is an arithmetic number, because the mean of its divisors is an integer number (572708682).

Almost surely, 2^21146156640 is an apocalyptic number.

21146156640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21146156640 is an abundant number, since it is smaller than the sum of its proper divisors (61323893568).

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

21146156640 is a wasteful number, since it uses less digits than its factorization.

21146156640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2097861 (or 2097850 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 21146156640 in words is "twenty-one billion, one hundred forty-six million, one hundred fifty-six thousand, six hundred forty".