15500222121 has 8 divisors (see below), whose sum is σ = 20691599040. Its totient is φ = 10321163312.

The previous prime is 15500222117. The next prime is 15500222131. The reversal of 15500222121 is 12122200551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 15500222121 - 2² = 15500222117 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (15500222131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3076590 + ... + 3081623.

It is an arithmetic number, because the mean of its divisors is an integer number (2586449880).

Almost surely, 2^15500222121 is an apocalyptic number.

It is an amenable number.

15500222121 is a deficient number, since it is larger than the sum of its proper divisors (5191376919).

15500222121 is an equidigital number, since it uses as much as digits as its factorization.

15500222121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6159055.

The product of its (nonzero) digits is 400, while the sum is 21.

Adding to 15500222121 its reverse (12122200551), we get a palindrome (27622422672).

The spelling of 15500222121 in words is "fifteen billion, five hundred million, two hundred twenty-two thousand, one hundred twenty-one".