21700507500 has 540 divisors, whose sum is σ = 82803400680. Its totient is φ = 4960116000.

The previous prime is 21700507471. The next prime is 21700507519. The reversal of 21700507500 is 570500712.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is a tau number, because it is divible by the number of its divisors (540).

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 179 ways as a sum of consecutive naturals, for example, 3100072497 + ... + 3100072503.

Almost surely, 2^21700507500 is an apocalyptic number.

21700507500 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 21700507500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41401700340).

21700507500 is an abundant number, since it is smaller than the sum of its proper divisors (61102893180).

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

21700507500 is an frugal number, since it uses more digits than its factorization.

21700507500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71 (or 17 counting only the distinct ones).

The product of its (nonzero) digits is 2450, while the sum is 27.

Multiplying 21700507500 by its sum of digits (27), we get a square (585913702500 = 765450²).

21700507500 divided by its sum of digits (27) gives a square (803722500 = 28350²).

The spelling of 21700507500 in words is "twenty-one billion, seven hundred million, five hundred seven thousand, five hundred".