15820781425 has 6 divisors (see below), whose sum is σ = 19617768998. Its totient is φ = 12656625120.

The previous prime is 15820781401. The next prime is 15820781429. The reversal of 15820781425 is 52418702851.

It can be written as a sum of positive squares in 3 ways, for example, as 4179234609 + 11641546816 = 64647^2 + 107896^2 .

It is not a de Polignac number, because 15820781425 - 2⁵ = 15820781393 is a prime.

It is a super-3 number, since 3×15820781425³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15820781429) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 316415604 + ... + 316415653.

Almost surely, 2^15820781425 is an apocalyptic number.

It is an amenable number.

15820781425 is a deficient number, since it is larger than the sum of its proper divisors (3796987573).

15820781425 is an equidigital number, since it uses as much as digits as its factorization.

15820781425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632831267 (or 632831262 counting only the distinct ones).

The product of its (nonzero) digits is 179200, while the sum is 43.

The spelling of 15820781425 in words is "fifteen billion, eight hundred twenty million, seven hundred eighty-one thousand, four hundred twenty-five".