81770157 has 48 divisors (see below), whose sum is σ = 140774400. Its totient is φ = 44755200.

The previous prime is 81770137. The next prime is 81770159. The reversal of 81770157 is 75107718.

It is not a de Polignac number, because 81770157 - 2¹⁵ = 81737389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81770159) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 290857 + ... + 291137.

It is an arithmetic number, because the mean of its divisors is an integer number (2932800).

Almost surely, 2^81770157 is an apocalyptic number.

It is an amenable number.

81770157 is a deficient number, since it is larger than the sum of its proper divisors (59004243).

81770157 is a wasteful number, since it uses less digits than its factorization.

81770157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474 (or 471 counting only the distinct ones).

The product of its (nonzero) digits is 13720, while the sum is 36.

The square root of 81770157 is about 9042.6852759565. The cubic root of 81770157 is about 434.0418546424.

The spelling of 81770157 in words is "eighty-one million, seven hundred seventy thousand, one hundred fifty-seven".