15722121 has 4 divisors (see below), whose sum is σ = 20962832. Its totient is φ = 10481412.

The previous prime is 15722099. The next prime is 15722149. The reversal of 15722121 is 12122751.

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 not a de Polignac number, because 15722121 - 2⁹ = 15721609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15722221) 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, 2620351 + ... + 2620356.

It is an arithmetic number, because the mean of its divisors is an integer number (5240708).

Almost surely, 2^15722121 is an apocalyptic number.

It is an amenable number.

15722121 is a deficient number, since it is larger than the sum of its proper divisors (5240711).

15722121 is an equidigital number, since it uses as much as digits as its factorization.

15722121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5240710.

The product of its digits is 280, while the sum is 21.

The square root of 15722121 is about 3965.1129870408. The cubic root of 15722121 is about 250.5169091498.

Adding to 15722121 its reverse (12122751), we get a palindrome (27844872).

The spelling of 15722121 in words is "fifteen million, seven hundred twenty-two thousand, one hundred twenty-one".