73931981 has 4 divisors (see below), whose sum is σ = 73953600. Its totient is φ = 73910364.

The previous prime is 73931951. The next prime is 73931989. The reversal of 73931981 is 18913937.

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 a cyclic number.

It is not a de Polignac number, because 73931981 - 2²² = 69737677 is a prime.

It is a super-2 number, since 2×73931981² = 10931875629168722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73931989) 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, 4421 + ... + 12938.

It is an arithmetic number, because the mean of its divisors is an integer number (18488400).

Almost surely, 2^73931981 is an apocalyptic number.

It is an amenable number.

73931981 is a deficient number, since it is larger than the sum of its proper divisors (21619).

73931981 is a wasteful number, since it uses less digits than its factorization.

73931981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21618.

The product of its digits is 40824, while the sum is 41.

The square root of 73931981 is about 8598.3708340592. The cubic root of 73931981 is about 419.7049723235.

The spelling of 73931981 in words is "seventy-three million, nine hundred thirty-one thousand, nine hundred eighty-one".