100990661 has 4 divisors (see below), whose sum is σ = 101100300. Its totient is φ = 100881024.

The previous prime is 100990657. The next prime is 100990663. The reversal of 100990661 is 166099001.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166099001 = 79 ⋅2102519.

It can be written as a sum of positive squares in 2 ways, for example, as 19088161 + 81902500 = 4369^2 + 9050^2 .

It is a cyclic number.

It is not a de Polignac number, because 100990661 - 2² = 100990657 is a prime.

It is a super-2 number, since 2×100990661² = 20398227218433842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100990663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53426 + ... + 55283.

It is an arithmetic number, because the mean of its divisors is an integer number (25275075).

Almost surely, 2^100990661 is an apocalyptic number.

It is an amenable number.

100990661 is a deficient number, since it is larger than the sum of its proper divisors (109639).

100990661 is an equidigital number, since it uses as much as digits as its factorization.

100990661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109638.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 100990661 is about 10049.4109777638. The cubic root of 100990661 is about 465.6865966047.

The spelling of 100990661 in words is "one hundred million, nine hundred ninety thousand, six hundred sixty-one".