6311981 has 12 divisors (see below), whose sum is σ = 7240212. Its totient is φ = 5483712.

The previous prime is 6311957. The next prime is 6311983. The reversal of 6311981 is 1891136.

6311981 = 103² + 104² + ... + 271².

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 6300100 + 11881 = 2510^2 + 109^2 .

It is not a de Polignac number, because 6311981 - 2²² = 2117677 is a prime.

It is a super-2 number, since 2×6311981² = 79682208288722, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6311983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 371285 + ... + 371301.

It is an arithmetic number, because the mean of its divisors is an integer number (603351).

Almost surely, 2^6311981 is an apocalyptic number.

It is an amenable number.

6311981 is a deficient number, since it is larger than the sum of its proper divisors (928231).

6311981 is an frugal number, since it uses more digits than its factorization.

6311981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82 (or 30 counting only the distinct ones).

The product of its digits is 1296, while the sum is 29.

The square root of 6311981 is about 2512.3656182968. The cubic root of 6311981 is about 184.8084796650.

The spelling of 6311981 in words is "six million, three hundred eleven thousand, nine hundred eighty-one".