15406661 has 4 divisors (see below), whose sum is σ = 15415500. Its totient is φ = 15397824.

The previous prime is 15406649. The next prime is 15406669. The reversal of 15406661 is 16660451.

15406661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 16660451 = 239 ⋅69709.

It can be written as a sum of positive squares in 2 ways, for example, as 10144225 + 5262436 = 3185^2 + 2294^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15406661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15406669) 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, 836 + ... + 5613.

It is an arithmetic number, because the mean of its divisors is an integer number (3853875).

Almost surely, 2^15406661 is an apocalyptic number.

It is an amenable number.

15406661 is a deficient number, since it is larger than the sum of its proper divisors (8839).

15406661 is an equidigital number, since it uses as much as digits as its factorization.

15406661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8838.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 15406661 is about 3925.1319723036. The cubic root of 15406661 is about 248.8300588246.

The spelling of 15406661 in words is "fifteen million, four hundred six thousand, six hundred sixty-one".