82561631 has 4 divisors (see below), whose sum is σ = 86907000. Its totient is φ = 78216264.

The previous prime is 82561561. The next prime is 82561643. The reversal of 82561631 is 13616528.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 82561631 - 2¹⁴ = 82545247 is a prime.

It is a super-2 number, since 2×82561631² = 13632845826760322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82561931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2172656 + ... + 2172693.

It is an arithmetic number, because the mean of its divisors is an integer number (21726750).

Almost surely, 2^82561631 is an apocalyptic number.

82561631 is a deficient number, since it is larger than the sum of its proper divisors (4345369).

82561631 is a wasteful number, since it uses less digits than its factorization.

82561631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4345368.

The product of its digits is 8640, while the sum is 32.

The square root of 82561631 is about 9086.3431038014. The cubic root of 82561631 is about 435.4377607489.

The spelling of 82561631 in words is "eighty-two million, five hundred sixty-one thousand, six hundred thirty-one".