99561979 has 8 divisors (see below), whose sum is σ = 115002288. Its totient is φ = 85186560.

The previous prime is 99561937. The next prime is 99561983. The reversal of 99561979 is 97916599.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 99561979 - 2²³ = 91173371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99561989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 266022 + ... + 266395.

It is an arithmetic number, because the mean of its divisors is an integer number (14375286).

Almost surely, 2^99561979 is an apocalyptic number.

99561979 is a deficient number, since it is larger than the sum of its proper divisors (15440309).

99561979 is a wasteful number, since it uses less digits than its factorization.

99561979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532445.

The product of its digits is 1377810, while the sum is 55.

The square root of 99561979 is about 9978.0749145314. The cubic root of 99561979 is about 463.4801869896.

It can be divided in two parts, 9956 and 1979, that added together give a triangular number (11935 = T₁₅₄).

The spelling of 99561979 in words is "ninety-nine million, five hundred sixty-one thousand, nine hundred seventy-nine".