991670940 has 72 divisors (see below), whose sum is σ = 3239466048. Its totient is φ = 244103040.

The previous prime is 991670891. The next prime is 991670941. The reversal of 991670940 is 49076199.

It is a super-2 number, since 2×991670940² = 1966822506480967200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991670941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 209556 + ... + 214235.

It is an arithmetic number, because the mean of its divisors is an integer number (44992584).

Almost surely, 2^991670940 is an apocalyptic number.

991670940 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

991670940 is an abundant number, since it is smaller than the sum of its proper divisors (2247795108).

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

991670940 is a wasteful number, since it uses less digits than its factorization.

991670940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423819 (or 423814 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The square root of 991670940 is about 31490.8072300473. The cubic root of 991670940 is about 997.2159026620.

The spelling of 991670940 in words is "nine hundred ninety-one million, six hundred seventy thousand, nine hundred forty".