81631698 has 16 divisors (see below), whose sum is σ = 163459296. Its totient is φ = 27177920.

The previous prime is 81631687. The next prime is 81631699. The reversal of 81631698 is 89613618.

It is not an unprimeable number, because it can be changed into a prime (81631699) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2436 + ... + 13007.

It is an arithmetic number, because the mean of its divisors is an integer number (10216206).

Almost surely, 2^81631698 is an apocalyptic number.

81631698 is an abundant number, since it is smaller than the sum of its proper divisors (81827598).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81631698 is a wasteful number, since it uses less digits than its factorization.

81631698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16329.

The product of its digits is 62208, while the sum is 42.

The square root of 81631698 is about 9035.0261759444. The cubic root of 81631698 is about 433.7967328055.

The spelling of 81631698 in words is "eighty-one million, six hundred thirty-one thousand, six hundred ninety-eight".