21157501075 has 6 divisors (see below), whose sum is σ = 26235301364. Its totient is φ = 16926000840.

The previous prime is 21157501031. The next prime is 21157501093. The reversal of 21157501075 is 57010575112.

It is a de Polignac number, because none of the positive numbers 2^k-21157501075 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21157501075.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 423149997 + ... + 423150046.

Almost surely, 2^21157501075 is an apocalyptic number.

21157501075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21157501075 is a deficient number, since it is larger than the sum of its proper divisors (5077800289).

21157501075 is an equidigital number, since it uses as much as digits as its factorization.

21157501075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 846300053 (or 846300048 counting only the distinct ones).

The product of its (nonzero) digits is 12250, while the sum is 34.

The spelling of 21157501075 in words is "twenty-one billion, one hundred fifty-seven million, five hundred one thousand, seventy-five".