81357031 has 8 divisors (see below), whose sum is σ = 97873280. Its totient is φ = 66064248.

The previous prime is 81357013. The next prime is 81357037. The reversal of 81357031 is 13075318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81357031 - 2⁵ = 81356999 is a prime.

It is a super-2 number, since 2×81357031² = 13237932986269922, 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 (81357037) 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, 305721 + ... + 305986.

It is an arithmetic number, because the mean of its divisors is an integer number (12234160).

Almost surely, 2^81357031 is an apocalyptic number.

81357031 is a deficient number, since it is larger than the sum of its proper divisors (16516249).

81357031 is a wasteful number, since it uses less digits than its factorization.

81357031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 611733.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 81357031 is about 9019.8132464037. The cubic root of 81357031 is about 433.3096526836.

The spelling of 81357031 in words is "eighty-one million, three hundred fifty-seven thousand, thirty-one".