100661945 has 4 divisors (see below), whose sum is σ = 120794340. Its totient is φ = 80529552.

The previous prime is 100661933. The next prime is 100661969. The reversal of 100661945 is 549166001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 549166001 = 47 ⋅11684383.

It can be written as a sum of positive squares in 2 ways, for example, as 26081449 + 74580496 = 5107^2 + 8636^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100661945 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10066190 + ... + 10066199.

It is an arithmetic number, because the mean of its divisors is an integer number (30198585).

Almost surely, 2^100661945 is an apocalyptic number.

It is an amenable number.

100661945 is a deficient number, since it is larger than the sum of its proper divisors (20132395).

100661945 is an equidigital number, since it uses as much as digits as its factorization.

100661945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20132394.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 100661945 is about 10033.0426591339. The cubic root of 100661945 is about 465.1807906858.

The spelling of 100661945 in words is "one hundred million, six hundred sixty-one thousand, nine hundred forty-five".