915213981 has 32 divisors (see below), whose sum is σ = 1373493888. Its totient is φ = 537200640.

The previous prime is 915213979. The next prime is 915213997. The reversal of 915213981 is 189312519.

It is not a de Polignac number, because 915213981 - 2¹ = 915213979 is a prime.

It is a super-2 number, since 2×915213981² = 1675233262035736722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (915218981) 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, 282885 + ... + 286101.

It is an arithmetic number, because the mean of its divisors is an integer number (42921684).

Almost surely, 2^915213981 is an apocalyptic number.

It is an amenable number.

915213981 is a deficient number, since it is larger than the sum of its proper divisors (458279907).

915213981 is a wasteful number, since it uses less digits than its factorization.

915213981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3501.

The product of its digits is 19440, while the sum is 39.

The square root of 915213981 is about 30252.5037145688. The cubic root of 915213981 is about 970.8993610791.

The spelling of 915213981 in words is "nine hundred fifteen million, two hundred thirteen thousand, nine hundred eighty-one".