22015915 has 4 divisors (see below), whose sum is σ = 26419104. Its totient is φ = 17612728.

The previous prime is 22015913. The next prime is 22015919. The reversal of 22015915 is 51951022.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51951022 = 2 ⋅25975511.

It is a cyclic number.

It is not a de Polignac number, because 22015915 - 2¹ = 22015913 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 22015915.

It is not an unprimeable number, because it can be changed into a prime (22015913) 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, 2201587 + ... + 2201596.

It is an arithmetic number, because the mean of its divisors is an integer number (6604776).

Almost surely, 2^22015915 is an apocalyptic number.

22015915 is a deficient number, since it is larger than the sum of its proper divisors (4403189).

22015915 is an equidigital number, since it uses as much as digits as its factorization.

22015915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4403188.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 22015915 is about 4692.1119978108. Note that the first 3 decimals coincide. The cubic root of 22015915 is about 280.2714841366.

Adding to 22015915 its reverse (51951022), we get a palindrome (73966937).

The spelling of 22015915 in words is "twenty-two million, fifteen thousand, nine hundred fifteen".