15751921 has 2 divisors, whose sum is σ = 15751922. Its totient is φ = 15751920.

The previous prime is 15751891. The next prime is 15751951. The reversal of 15751921 is 12915751.

It is a balanced prime because it is at equal distance from previous prime (15751891) and next prime (15751951).

It can be written as a sum of positive squares in only one way, i.e., 9991921 + 5760000 = 3161^2 + 2400^2 .

It is an emirp because it is prime and its reverse (12915751) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15751921 - 2⁷ = 15751793 is a prime.

It is not a weakly prime, because it can be changed into another prime (15751951) 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, 7875960 + 7875961.

It is an arithmetic number, because the mean of its divisors is an integer number (7875961).

Almost surely, 2^15751921 is an apocalyptic number.

It is an amenable number.

15751921 is a deficient number, since it is larger than the sum of its proper divisors (1).

15751921 is an equidigital number, since it uses as much as digits as its factorization.

15751921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3150, while the sum is 31.

The square root of 15751921 is about 3968.8689824684. The cubic root of 15751921 is about 250.6750873872.

The spelling of 15751921 in words is "fifteen million, seven hundred fifty-one thousand, nine hundred twenty-one".