999621957 has 16 divisors (see below), whose sum is σ = 1350236160. Its totient is φ = 657748992.

The previous prime is 999621937. The next prime is 999621971. The reversal of 999621957 is 759126999.

It is not a de Polignac number, because 999621957 - 2⁶ = 999621893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 999621897 and 999621906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999621907) 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, 106969 + ... + 115937.

It is an arithmetic number, because the mean of its divisors is an integer number (84389760).

Almost surely, 2^999621957 is an apocalyptic number.

999621957 is a gapful number since it is divisible by the number (97) formed by its first and last digit.

It is an amenable number.

999621957 is a deficient number, since it is larger than the sum of its proper divisors (350614203).

999621957 is a wasteful number, since it uses less digits than its factorization.

999621957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9452.

The product of its digits is 2755620, while the sum is 57.

The square root of 999621957 is about 31616.7986519825. The cubic root of 999621957 is about 999.8739697837.

The spelling of 999621957 in words is "nine hundred ninety-nine million, six hundred twenty-one thousand, nine hundred fifty-seven".