15221261 has 16 divisors (see below), whose sum is σ = 17756160. Its totient is φ = 12901680.

The previous prime is 15221251. The next prime is 15221263. The reversal of 15221261 is 16212251.

15221261 = 169² + 170² + ... + 369².

It is not a de Polignac number, because 15221261 - 2⁶ = 15221197 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 (15221263) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13460 + ... + 14546.

It is an arithmetic number, because the mean of its divisors is an integer number (1109760).

Almost surely, 2^15221261 is an apocalyptic number.

15221261 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15221261 is a deficient number, since it is larger than the sum of its proper divisors (2534899).

15221261 is a wasteful number, since it uses less digits than its factorization.

15221261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1184.

The product of its digits is 240, while the sum is 20.

The square root of 15221261 is about 3901.4434508269. The cubic root of 15221261 is about 247.8279080551.

The spelling of 15221261 in words is "fifteen million, two hundred twenty-one thousand, two hundred sixty-one".