1256609977979 has 16 divisors (see below), whose sum is σ = 1311870193920. Its totient is φ = 1202151982080.

The previous prime is 1256609977963. The next prime is 1256609978011. The reversal of 1256609977979 is 9797799066521.

It is a cyclic number.

It is not a de Polignac number, because 1256609977979 - 2⁴ = 1256609977963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1256609947979) 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, 10317719 + ... + 10438799.

It is an arithmetic number, because the mean of its divisors is an integer number (81991887120).

Almost surely, 2^{1256609977979} is an apocalyptic number.

1256609977979 is a deficient number, since it is larger than the sum of its proper divisors (55260215941).

1256609977979 is a wasteful number, since it uses less digits than its factorization.

1256609977979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124390.

The product of its (nonzero) digits is 810152280, while the sum is 77.

The spelling of 1256609977979 in words is "one trillion, two hundred fifty-six billion, six hundred nine million, nine hundred seventy-seven thousand, nine hundred seventy-nine".