15661101225 has 96 divisors (see below), whose sum is σ = 32361928704. Its totient is φ = 6492441600.

The previous prime is 15661101191. The next prime is 15661101229. The reversal of 15661101225 is 52210116651.

It is not a de Polignac number, because 15661101225 - 2¹⁰ = 15661100201 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 15661101192 and 15661101201.

It is not an unprimeable number, because it can be changed into a prime (15661101229) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2497444 + ... + 2503706.

It is an arithmetic number, because the mean of its divisors is an integer number (337103424).

Almost surely, 2^15661101225 is an apocalyptic number.

15661101225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

15661101225 is an abundant number, since it is smaller than the sum of its proper divisors (16700827479).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15661101225 is a wasteful number, since it uses less digits than its factorization.

15661101225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6727 (or 6722 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 30.

Adding to 15661101225 its reverse (52210116651), we get a palindrome (67871217876).

It can be divided in two parts, 1566110 and 1225, that added together give a triangular number (1567335 = T₁₇₇₀).

The spelling of 15661101225 in words is "fifteen billion, six hundred sixty-one million, one hundred one thousand, two hundred twenty-five".