21345415 has 32 divisors (see below), whose sum is σ = 32288256. Its totient is φ = 13184640.

The previous prime is 21345413. The next prime is 21345427. The reversal of 21345415 is 51454312.

It is a happy number.

It is not a de Polignac number, because 21345415 - 2¹ = 21345413 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21345415.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345413) 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, 19020 + ... + 20110.

It is an arithmetic number, because the mean of its divisors is an integer number (1009008).

Almost surely, 2^21345415 is an apocalyptic number.

21345415 is a deficient number, since it is larger than the sum of its proper divisors (10942841).

21345415 is a wasteful number, since it uses less digits than its factorization.

21345415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1159.

The product of its digits is 2400, while the sum is 25.

The square root of 21345415 is about 4620.1098471790. The cubic root of 21345415 is about 277.3968558585.

Adding to 21345415 its reverse (51454312), we get a palindrome (72799727).

The spelling of 21345415 in words is "twenty-one million, three hundred forty-five thousand, four hundred fifteen".