15921761 has 2 divisors, whose sum is σ = 15921762. Its totient is φ = 15921760.

The previous prime is 15921749. The next prime is 15921769. The reversal of 15921761 is 16712951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15523600 + 398161 = 3940^2 + 631^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15921761 is a prime.

It is a super-2 number, since 2×15921761² = 507004946682242, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (15921769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7960880 + 7960881.

It is an arithmetic number, because the mean of its divisors is an integer number (7960881).

Almost surely, 2^15921761 is an apocalyptic number.

It is an amenable number.

15921761 is a deficient number, since it is larger than the sum of its proper divisors (1).

15921761 is an equidigital number, since it uses as much as digits as its factorization.

15921761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3780, while the sum is 32.

The square root of 15921761 is about 3990.2081399346. The cubic root of 15921761 is about 251.5728096620.

The spelling of 15921761 in words is "fifteen million, nine hundred twenty-one thousand, seven hundred sixty-one".