918913521 has 4 divisors (see below), whose sum is σ = 1225218032. Its totient is φ = 612609012.

The previous prime is 918913507. The next prime is 918913579. The reversal of 918913521 is 125319819.

918913521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is not a de Polignac number, because 918913521 - 2¹³ = 918905329 is a prime.

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 918913521.

It is not an unprimeable number, because it can be changed into a prime (918912521) 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, 153152251 + ... + 153152256.

It is an arithmetic number, because the mean of its divisors is an integer number (306304508).

Almost surely, 2^918913521 is an apocalyptic number.

It is an amenable number.

918913521 is a deficient number, since it is larger than the sum of its proper divisors (306304511).

918913521 is a wasteful number, since it uses less digits than its factorization.

918913521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306304510.

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

The square root of 918913521 is about 30313.5864093974. The cubic root of 918913521 is about 972.2058140525.

The spelling of 918913521 in words is "nine hundred eighteen million, nine hundred thirteen thousand, five hundred twenty-one".