251021132505155 has 4 divisors (see below), whose sum is σ = 301225359006192. Its totient is φ = 200816906004120.

The previous prime is 251021132505103. The next prime is 251021132505173. The reversal of 251021132505155 is 551505231120152.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 251021132505155 - 2⁸ = 251021132504899 is a prime.

It is a super-2 number, since 2×251021132505155² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25102113250511 + ... + 25102113250520.

It is an arithmetic number, because the mean of its divisors is an integer number (75306339751548).

Almost surely, 2^{251021132505155} is an apocalyptic number.

251021132505155 is a deficient number, since it is larger than the sum of its proper divisors (50204226501037).

251021132505155 is an equidigital number, since it uses as much as digits as its factorization.

251021132505155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50204226501036.

The product of its (nonzero) digits is 75000, while the sum is 38.

The spelling of 251021132505155 in words is "two hundred fifty-one trillion, twenty-one billion, one hundred thirty-two million, five hundred five thousand, one hundred fifty-five".