31505152121 has 4 divisors (see below), whose sum is σ = 31505638500. Its totient is φ = 31504665744.

The previous prime is 31505152103. The next prime is 31505152177. The reversal of 31505152121 is 12125150513.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12125150513 = 7 ⋅1732164359.

It can be written as a sum of positive squares in 2 ways, for example, as 14145772096 + 17359380025 = 118936^2 + 131755^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31505152121 is a prime.

It is a super-2 number, since 2×31505152121² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31505152421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127766 + ... + 281663.

It is an arithmetic number, because the mean of its divisors is an integer number (7876409625).

Almost surely, 2^31505152121 is an apocalyptic number.

It is an amenable number.

31505152121 is a deficient number, since it is larger than the sum of its proper divisors (486379).

31505152121 is an equidigital number, since it uses as much as digits as its factorization.

31505152121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 486378.

The product of its (nonzero) digits is 1500, while the sum is 26.

The spelling of 31505152121 in words is "thirty-one billion, five hundred five million, one hundred fifty-two thousand, one hundred twenty-one".