81701587 has 16 divisors (see below), whose sum is σ = 92104704. Its totient is φ = 71820000.

The previous prime is 81701573. The next prime is 81701597. The reversal of 81701587 is 78510718.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81701587 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81701537) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 77212 + ... + 78262.

It is an arithmetic number, because the mean of its divisors is an integer number (5756544).

Almost surely, 2^81701587 is an apocalyptic number.

81701587 is a deficient number, since it is larger than the sum of its proper divisors (10403117).

81701587 is a wasteful number, since it uses less digits than its factorization.

81701587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1290.

The product of its (nonzero) digits is 15680, while the sum is 37.

The square root of 81701587 is about 9038.8930185062. The cubic root of 81701587 is about 433.9204958884.

81701587 divided by its sum of digits (37) gives a triangular number (2208151 = T₂₁₀₁).

The spelling of 81701587 in words is "eighty-one million, seven hundred one thousand, five hundred eighty-seven".