77731993 has 4 divisors (see below), whose sum is σ = 78892240. Its totient is φ = 76571748.

The previous prime is 77731991. The next prime is 77731999. The reversal of 77731993 is 39913777.

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 77731993 - 2¹ = 77731991 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77731991) 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, 580023 + ... + 580156.

It is an arithmetic number, because the mean of its divisors is an integer number (19723060).

Almost surely, 2^77731993 is an apocalyptic number.

It is an amenable number.

77731993 is a deficient number, since it is larger than the sum of its proper divisors (1160247).

77731993 is a wasteful number, since it uses less digits than its factorization.

77731993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1160246.

The product of its digits is 250047, while the sum is 46.

The square root of 77731993 is about 8816.5749018539. The cubic root of 77731993 is about 426.7759466041.

The spelling of 77731993 in words is "seventy-seven million, seven hundred thirty-one thousand, nine hundred ninety-three".