21011009975 has 6 divisors (see below), whose sum is σ = 26053652400. Its totient is φ = 16808807960.

The previous prime is 21011009969. The next prime is 21011009993. The reversal of 21011009975 is 57990011012.

It is a de Polignac number, because none of the positive numbers 2^k-21011009975 is a prime.

It is a congruent number.

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, 420220175 + ... + 420220224.

It is an arithmetic number, because the mean of its divisors is an integer number (4342275400).

Almost surely, 2^21011009975 is an apocalyptic number.

21011009975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21011009975 is a deficient number, since it is larger than the sum of its proper divisors (5042642425).

21011009975 is an equidigital number, since it uses as much as digits as its factorization.

21011009975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840440409 (or 840440404 counting only the distinct ones).

The product of its (nonzero) digits is 5670, while the sum is 35.

The spelling of 21011009975 in words is "twenty-one billion, eleven million, nine thousand, nine hundred seventy-five".