15790721 has 8 divisors (see below), whose sum is σ = 16020840. Its totient is φ = 15562368.

The previous prime is 15790717. The next prime is 15790741. The reversal of 15790721 is 12709751.

It can be written as a sum of positive squares in 4 ways, for example, as 2686321 + 13104400 = 1639^2 + 3620^2 .

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 15790721 - 2² = 15790717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15790711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34325 + ... + 34781.

It is an arithmetic number, because the mean of its divisors is an integer number (2002605).

Almost surely, 2^15790721 is an apocalyptic number.

It is an amenable number.

15790721 is a deficient number, since it is larger than the sum of its proper divisors (230119).

15790721 is a wasteful number, since it uses less digits than its factorization.

15790721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 883.

The product of its (nonzero) digits is 4410, while the sum is 32.

The square root of 15790721 is about 3973.7540185573. The cubic root of 15790721 is about 250.8807388857.

The spelling of 15790721 in words is "fifteen million, seven hundred ninety thousand, seven hundred twenty-one".