1251121531 has 4 divisors (see below), whose sum is σ = 1364859864. Its totient is φ = 1137383200.

The previous prime is 1251121517. The next prime is 1251121537. The reversal of 1251121531 is 1351211521.

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

It is a cyclic number.

It is not a de Polignac number, because 1251121531 - 2¹⁷ = 1250990459 is a prime.

It is a super-2 number, since 2×1251121531² = 3130610170663567922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1251121537) 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, 56869150 + ... + 56869171.

It is an arithmetic number, because the mean of its divisors is an integer number (341214966).

Almost surely, 2^1251121531 is an apocalyptic number.

1251121531 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1251121531 is a deficient number, since it is larger than the sum of its proper divisors (113738333).

1251121531 is a wasteful number, since it uses less digits than its factorization.

1251121531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113738332.

The product of its digits is 300, while the sum is 22.

The square root of 1251121531 is about 35371.1963467452. The cubic root of 1251121531 is about 1077.5394174170.

The spelling of 1251121531 in words is "one billion, two hundred fifty-one million, one hundred twenty-one thousand, five hundred thirty-one".