15981415981 has 8 divisors (see below), whose sum is σ = 16975567224. Its totient is φ = 14993272320.

The previous prime is 15981415973. The next prime is 15981415993. The reversal of 15981415981 is 18951418951.

It can be written as a sum of positive squares in 4 ways, for example, as 2463633225 + 13517782756 = 49635^2 + 116266^2 .

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 15981415981 - 2³ = 15981415973 is a prime.

It is a super-2 number, since 2×15981415981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15981415921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1496410 + ... + 1507051.

It is an arithmetic number, because the mean of its divisors is an integer number (2121945903).

Almost surely, 2^15981415981 is an apocalyptic number.

It is an amenable number.

15981415981 is a deficient number, since it is larger than the sum of its proper divisors (994151243).

15981415981 is a wasteful number, since it uses less digits than its factorization.

15981415981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3003791.

The product of its digits is 518400, while the sum is 52.

The spelling of 15981415981 in words is "fifteen billion, nine hundred eighty-one million, four hundred fifteen thousand, nine hundred eighty-one".