81700037 has 4 divisors (see below), whose sum is σ = 82114956. Its totient is φ = 81285120.

The previous prime is 81700009. The next prime is 81700039. The reversal of 81700037 is 73000718.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 78605956 + 3094081 = 8866^2 + 1759^2 .

It is a cyclic number.

It is not a de Polignac number, because 81700037 - 2⁸ = 81699781 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81699979 and 81700015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81700039) 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, 207164 + ... + 207557.

It is an arithmetic number, because the mean of its divisors is an integer number (20528739).

Almost surely, 2^81700037 is an apocalyptic number.

It is an amenable number.

81700037 is a deficient number, since it is larger than the sum of its proper divisors (414919).

81700037 is a wasteful number, since it uses less digits than its factorization.

81700037 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414918.

The product of its (nonzero) digits is 1176, while the sum is 26.

The square root of 81700037 is about 9038.8072775118. The cubic root of 81700037 is about 433.9177518331.

The spelling of 81700037 in words is "eighty-one million, seven hundred thousand, thirty-seven".