2631978261 has 24 divisors (see below), whose sum is σ = 4187641536. Its totient is φ = 1579645440.

The previous prime is 2631978257. The next prime is 2631978269. The reversal of 2631978261 is 1628791362.

2631978261 is a `hidden beast` number, since 2 + 6 + 319 + 78 + 261 = 666.

It is not a de Polignac number, because 2631978261 - 2² = 2631978257 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2631978269) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 118860 + ... + 139253.

It is an arithmetic number, because the mean of its divisors is an integer number (174485064).

Almost surely, 2^2631978261 is an apocalyptic number.

It is an amenable number.

2631978261 is a deficient number, since it is larger than the sum of its proper divisors (1555663275).

2631978261 is a wasteful number, since it uses less digits than its factorization.

2631978261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258233 (or 258230 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 2631978261 is about 51302.8094844717. The cubic root of 2631978261 is about 1380.6833871082.

The spelling of 2631978261 in words is "two billion, six hundred thirty-one million, nine hundred seventy-eight thousand, two hundred sixty-one".