15509945 has 16 divisors (see below), whose sum is σ = 20587392. Its totient is φ = 11122560.

The previous prime is 15509927. The next prime is 15509957. The reversal of 15509945 is 54990551.

It is not a de Polignac number, because 15509945 - 2¹⁴ = 15493561 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15509899 and 15509908.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2084 + ... + 5946.

It is an arithmetic number, because the mean of its divisors is an integer number (1286712).

Almost surely, 2^15509945 is an apocalyptic number.

It is an amenable number.

15509945 is a deficient number, since it is larger than the sum of its proper divisors (5077447).

15509945 is a wasteful number, since it uses less digits than its factorization.

15509945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3952.

The product of its (nonzero) digits is 40500, while the sum is 38.

The square root of 15509945 is about 3938.2667507420. The cubic root of 15509945 is about 249.3848609907.

The spelling of 15509945 in words is "fifteen million, five hundred nine thousand, nine hundred forty-five".