161658987 has 16 divisors (see below), whose sum is σ = 251366400. Its totient is φ = 92375976.

The previous prime is 161658971. The next prime is 161659009. The reversal of 161658987 is 789856161.

161658987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 161658987 - 2⁴ = 161658971 is a prime.

It is a super-2 number, since 2×161658987² = 52267256155732338, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (161658947) 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, 77523 + ... + 79580.

It is an arithmetic number, because the mean of its divisors is an integer number (15710400).

Almost surely, 2^161658987 is an apocalyptic number.

161658987 is a deficient number, since it is larger than the sum of its proper divisors (89707413).

161658987 is an equidigital number, since it uses as much as digits as its factorization.

161658987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157127 (or 157113 counting only the distinct ones).

The product of its digits is 725760, while the sum is 51.

The square root of 161658987 is about 12714.5187482657. The cubic root of 161658987 is about 544.7534018905.

It can be divided in two parts, 16165 and 8987, that added together give a palindrome (25152).

The spelling of 161658987 in words is "one hundred sixty-one million, six hundred fifty-eight thousand, nine hundred eighty-seven".