311904861981 has 4 divisors (see below), whose sum is σ = 415873149312. Its totient is φ = 207936574652.

The previous prime is 311904861959. The next prime is 311904862013. The reversal of 311904861981 is 189168409113.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 189168409113 = 3 ⋅63056136371.

It is a cyclic number.

It is not a de Polignac number, because 311904861981 - 2¹⁴ = 311904845597 is a prime.

It is a super-2 number, since 2×311904861981² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311904861901) 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, 51984143661 + ... + 51984143666.

It is an arithmetic number, because the mean of its divisors is an integer number (103968287328).

Almost surely, 2^311904861981 is an apocalyptic number.

It is an amenable number.

311904861981 is a deficient number, since it is larger than the sum of its proper divisors (103968287331).

311904861981 is a wasteful number, since it uses less digits than its factorization.

311904861981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103968287330.

The product of its (nonzero) digits is 373248, while the sum is 51.

The spelling of 311904861981 in words is "three hundred eleven billion, nine hundred four million, eight hundred sixty-one thousand, nine hundred eighty-one".