81907874 has 4 divisors (see below), whose sum is σ = 122861814. Its totient is φ = 40953936.

The previous prime is 81907831. The next prime is 81907877. The reversal of 81907874 is 47870918.

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

It can be written as a sum of positive squares in only one way, i.e., 76650025 + 5257849 = 8755^2 + 2293^2 .

It is not an unprimeable number, because it can be changed into a prime (81907877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20476967 + ... + 20476970.

Almost surely, 2^81907874 is an apocalyptic number.

81907874 is a deficient number, since it is larger than the sum of its proper divisors (40953940).

81907874 is a wasteful number, since it uses less digits than its factorization.

81907874 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40953939.

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 81907874 is about 9050.2969012072. The cubic root of 81907874 is about 434.2853885431.

The spelling of 81907874 in words is "eighty-one million, nine hundred seven thousand, eight hundred seventy-four".