999981057 has 16 divisors (see below), whose sum is σ = 1345372928.
Its totient is φ = 660648960.
The previous prime is 999981049. The next prime is 999981061. The reversal of 999981057 is 750189999.
It is not a de Polignac number, because 999981057 - 23 = 999981049 is a prime.
It is a super-2 number, since 2×9999810572 = 1999924228717674498, which contains 22 as substring.
It is a Duffinian number.
It is a junction number, because it is equal to n+sod(n) for n = 999980988 and 999981006.
It is not an unprimeable number, because it can be changed into a prime (999980057) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 153723 + ... + 160095.
It is an arithmetic number, because the mean of its divisors is an integer number (84085808).
It is a Proth number, since it is equal to 30517 ⋅ 215 + 1 and 30517 < 215.
Almost surely, 2999981057 is an apocalyptic number.
It is an amenable number.
999981057 is a deficient number, since it is larger than the sum of its proper divisors (345391871).
999981057 is a wasteful number, since it uses less digits than its factorization.
999981057 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 6840.
The product of its (nonzero) digits is 1837080, while the sum is 57.
The square root of 999981057 is about 31622.4770851368.
The cubic root of 999981057 is about 999.9936856268.
The spelling of 999981057 in words is "nine hundred ninety-nine million, nine hundred eighty-one thousand, fifty-seven".