1256121979 has 16 divisors (see below), whose sum is σ = 1491667200. Its totient is φ = 1034931744.

The previous prime is 1256121949. The next prime is 1256121983. The reversal of 1256121979 is 9791216521.

It is not a de Polignac number, because 1256121979 - 2⁹ = 1256121467 is a prime.

It is a super-2 number, since 2×1256121979² = 3155684852253752882, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1256121929) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32452 + ... + 59710.

It is an arithmetic number, because the mean of its divisors is an integer number (93229200).

Almost surely, 2^1256121979 is an apocalyptic number.

1256121979 is a deficient number, since it is larger than the sum of its proper divisors (235545221).

1256121979 is a wasteful number, since it uses less digits than its factorization.

1256121979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27522.

The product of its digits is 68040, while the sum is 43.

The square root of 1256121979 is about 35441.8111698598. The cubic root of 1256121979 is about 1078.9730690502.

The spelling of 1256121979 in words is "one billion, two hundred fifty-six million, one hundred twenty-one thousand, nine hundred seventy-nine".