999621623 has 16 divisors (see below), whose sum is σ = 1342150656. Its totient is φ = 719007840.

The previous prime is 999621613. The next prime is 999621643. The reversal of 999621623 is 326126999.

It is a cyclic number.

It is not a de Polignac number, because 999621623 - 2¹⁴ = 999605239 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999621613) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 498311 + ... + 500312.

It is an arithmetic number, because the mean of its divisors is an integer number (83884416).

Almost surely, 2^999621623 is an apocalyptic number.

999621623 is a deficient number, since it is larger than the sum of its proper divisors (342529033).

999621623 is a wasteful number, since it uses less digits than its factorization.

999621623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 998654.

The product of its digits is 314928, while the sum is 47.

The square root of 999621623 is about 31616.7933699798. The cubic root of 999621623 is about 999.8738584223.

The spelling of 999621623 in words is "nine hundred ninety-nine million, six hundred twenty-one thousand, six hundred twenty-three".