623393991 has 24 divisors (see below), whose sum is σ = 983114496. Its totient is φ = 377508240.

The previous prime is 623393959. The next prime is 623394017. The reversal of 623393991 is 199393326.

It is not a de Polignac number, because 623393991 - 2⁵ = 623393959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (623393191) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 204706 + ... + 207728.

It is an arithmetic number, because the mean of its divisors is an integer number (40963104).

Almost surely, 2^623393991 is an apocalyptic number.

623393991 is a deficient number, since it is larger than the sum of its proper divisors (359720505).

623393991 is a wasteful number, since it uses less digits than its factorization.

623393991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5123 (or 5120 counting only the distinct ones).

The product of its digits is 236196, while the sum is 45.

The square root of 623393991 is about 24967.8591593272. The cubic root of 623393991 is about 854.2550153702.

The spelling of 623393991 in words is "six hundred twenty-three million, three hundred ninety-three thousand, nine hundred ninety-one".