999621955 has 16 divisors (see below), whose sum is σ = 1221204960. Its totient is φ = 785288448.

The previous prime is 999621937. The next prime is 999621971. The reversal of 999621955 is 559126999.

It is a cyclic number.

It is not a de Polignac number, because 999621955 - 2⁷ = 999621827 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 999621896 and 999621905.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 516169 + ... + 518101.

It is an arithmetic number, because the mean of its divisors is an integer number (76325310).

Almost surely, 2^999621955 is an apocalyptic number.

999621955 is a deficient number, since it is larger than the sum of its proper divisors (221583005).

999621955 is a wasteful number, since it uses less digits than its factorization.

With its successor (999621956) it forms an eRAP, since the sums of their prime factors are consecutive (3750 and 3751).

999621955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3750.

The product of its digits is 1968300, while the sum is 55.

The square root of 999621955 is about 31616.7986203537. The cubic root of 999621955 is about 999.8739691169.

The spelling of 999621955 in words is "nine hundred ninety-nine million, six hundred twenty-one thousand, nine hundred fifty-five".