81157701 has 4 divisors (see below), whose sum is σ = 108210272. Its totient is φ = 54105132.

The previous prime is 81157697. The next prime is 81157723. The reversal of 81157701 is 10775118.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81157701 - 2² = 81157697 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81157781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13526281 + ... + 13526286.

It is an arithmetic number, because the mean of its divisors is an integer number (27052568).

Almost surely, 2^81157701 is an apocalyptic number.

It is an amenable number.

81157701 is a deficient number, since it is larger than the sum of its proper divisors (27052571).

81157701 is a wasteful number, since it uses less digits than its factorization.

81157701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27052570.

The product of its (nonzero) digits is 1960, while the sum is 30.

The square root of 81157701 is about 9008.7569064772. The cubic root of 81157701 is about 432.9554843679.

The spelling of 81157701 in words is "eighty-one million, one hundred fifty-seven thousand, seven hundred one".