15813542381 has 32 divisors (see below), whose sum is σ = 19731774720. Its totient is φ = 12339454464.

The previous prime is 15813542377. The next prime is 15813542387. The reversal of 15813542381 is 18324531851.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 15813542381 - 2² = 15813542377 is a prime.

It is a super-2 number, since 2×15813542381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15813542387) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5353601 + ... + 5356553.

It is an arithmetic number, because the mean of its divisors is an integer number (616617960).

Almost surely, 2^15813542381 is an apocalyptic number.

It is an amenable number.

15813542381 is a deficient number, since it is larger than the sum of its proper divisors (3918232339).

15813542381 is a wasteful number, since it uses less digits than its factorization.

15813542381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3765.

The product of its digits is 115200, while the sum is 41.

The spelling of 15813542381 in words is "fifteen billion, eight hundred thirteen million, five hundred forty-two thousand, three hundred eighty-one".