15735947981 has 4 divisors (see below), whose sum is σ = 16946405532. Its totient is φ = 14525490432.

The previous prime is 15735947957. The next prime is 15735947993. The reversal of 15735947981 is 18974953751.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18974953751 = 13 ⋅1459611827.

It can be written as a sum of positive squares in 2 ways, for example, as 938441956 + 14797506025 = 30634^2 + 121645^2 .

It is a cyclic number.

It is not a de Polignac number, because 15735947981 - 2⁶ = 15735947917 is a prime.

It is a super-2 number, since 2×15735947981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 15735947981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15735947081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 605228756 + ... + 605228781.

It is an arithmetic number, because the mean of its divisors is an integer number (4236601383).

Almost surely, 2^15735947981 is an apocalyptic number.

It is an amenable number.

15735947981 is a deficient number, since it is larger than the sum of its proper divisors (1210457551).

15735947981 is a wasteful number, since it uses less digits than its factorization.

15735947981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1210457550.

The product of its digits is 9525600, while the sum is 59.

The spelling of 15735947981 in words is "fifteen billion, seven hundred thirty-five million, nine hundred forty-seven thousand, nine hundred eighty-one".