15445251661 has 4 divisors (see below), whose sum is σ = 17651716192. Its totient is φ = 13238787132.

The previous prime is 15445251629. The next prime is 15445251673. The reversal of 15445251661 is 16615254451.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 15445251661 - 2⁵ = 15445251629 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 (15445251611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1103232255 + ... + 1103232268.

It is an arithmetic number, because the mean of its divisors is an integer number (4412929048).

Almost surely, 2^15445251661 is an apocalyptic number.

It is an amenable number.

15445251661 is a deficient number, since it is larger than the sum of its proper divisors (2206464531).

15445251661 is an equidigital number, since it uses as much as digits as its factorization.

15445251661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2206464530.

The product of its digits is 144000, while the sum is 40.

The spelling of 15445251661 in words is "fifteen billion, four hundred forty-five million, two hundred fifty-one thousand, six hundred sixty-one".