21151145520 has 160 divisors (see below), whose sum is σ = 73009612800. Its totient is φ = 5628254976.

The previous prime is 21151145443. The next prime is 21151145567. The reversal of 21151145520 is 2554115112.

It is a happy number.

21151145520 is a `hidden beast` number, since 21 + 1 + 5 + 114 + 5 + 520 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1024419 + ... + 1044861.

It is an arithmetic number, because the mean of its divisors is an integer number (456310080).

Almost surely, 2^21151145520 is an apocalyptic number.

21151145520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21151145520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36504806400).

21151145520 is an abundant number, since it is smaller than the sum of its proper divisors (51858467280).

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

21151145520 is a wasteful number, since it uses less digits than its factorization.

21151145520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20944 (or 20932 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 27.

The spelling of 21151145520 in words is "twenty-one billion, one hundred fifty-one million, one hundred forty-five thousand, five hundred twenty".