15382911981 has 4 divisors (see below), whose sum is σ = 20510549312. Its totient is φ = 10255274652.

The previous prime is 15382911961. The next prime is 15382911991. The reversal of 15382911981 is 18911928351.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18911928351 = 3 ⋅6303976117.

It is not a de Polignac number, because 15382911981 - 2¹⁰ = 15382910957 is a prime.

It is a super-2 number, since 2×15382911981² (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 15382911981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15382911961) 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, 2563818661 + ... + 2563818666.

It is an arithmetic number, because the mean of its divisors is an integer number (5127637328).

Almost surely, 2^15382911981 is an apocalyptic number.

It is an amenable number.

15382911981 is a deficient number, since it is larger than the sum of its proper divisors (5127637331).

15382911981 is an equidigital number, since it uses as much as digits as its factorization.

15382911981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5127637330.

The product of its digits is 155520, while the sum is 48.

The spelling of 15382911981 in words is "fifteen billion, three hundred eighty-two million, nine hundred eleven thousand, nine hundred eighty-one".