21164071500 has 768 divisors, whose sum is σ = 84830054400. Its totient is φ = 4478976000.

The previous prime is 21164071499. The next prime is 21164071517. The reversal of 21164071500 is 517046112.

It is a happy number.

21164071500 is a `hidden beast` number, since 2 + 1 + 1 + 640 + 7 + 15 + 0 + 0 = 666.

It is a super-2 number, since 2×21164071500² (a number of 21 digits) contains 22 as substring.

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 255 ways as a sum of consecutive naturals, for example, 36679212 + ... + 36679788.

It is an arithmetic number, because the mean of its divisors is an integer number (110455800).

Almost surely, 2^21164071500 is an apocalyptic number.

21164071500 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 21164071500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42415027200).

21164071500 is an abundant number, since it is smaller than the sum of its proper divisors (63665982900).

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

21164071500 is a wasteful number, since it uses less digits than its factorization.

21164071500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648 (or 630 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The spelling of 21164071500 in words is "twenty-one billion, one hundred sixty-four million, seventy-one thousand, five hundred".