999961980 has 24 divisors (see below), whose sum is σ = 2799893712. Its totient is φ = 266656512.

The previous prime is 999961979. The next prime is 999962057. The reversal of 999961980 is 89169999.

It is a super-2 number, since 2×999961980² = 1999847922891040800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (60), and also a Moran number because the ratio is a prime number: 16666033 = 999961980 / (9 + 9 + 9 + 9 + 6 + 1 + 9 + 8 + 0).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8332957 + ... + 8333076.

It is an arithmetic number, because the mean of its divisors is an integer number (116662238).

Almost surely, 2^999961980 is an apocalyptic number.

It is an amenable number.

999961980 is an abundant number, since it is smaller than the sum of its proper divisors (1799931732).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999961980 is a wasteful number, since it uses less digits than its factorization.

999961980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16666045 (or 16666043 counting only the distinct ones).

The product of its (nonzero) digits is 2834352, while the sum is 60.

The square root of 999961980 is about 31622.1754469866. The cubic root of 999961980 is about 999.9873265060.

The spelling of 999961980 in words is "nine hundred ninety-nine million, nine hundred sixty-one thousand, nine hundred eighty".