15661442 has 4 divisors (see below), whose sum is σ = 23492166. Its totient is φ = 7830720.

The previous prime is 15661441. The next prime is 15661463. The reversal of 15661442 is 24416651.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 14737921 + 923521 = 3839^2 + 961^2 .

It is not an unprimeable number, because it can be changed into a prime (15661441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3915359 + ... + 3915362.

Almost surely, 2^15661442 is an apocalyptic number.

15661442 is a deficient number, since it is larger than the sum of its proper divisors (7830724).

15661442 is an equidigital number, since it uses as much as digits as its factorization.

15661442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7830723.

The product of its digits is 5760, while the sum is 29.

The square root of 15661442 is about 3957.4539795176. The cubic root of 15661442 is about 250.1942064297.

The spelling of 15661442 in words is "fifteen million, six hundred sixty-one thousand, four hundred forty-two".