21052415 has 8 divisors (see below), whose sum is σ = 25288848. Its totient is φ = 16824640.

The previous prime is 21052411. The next prime is 21052469. The reversal of 21052415 is 51425012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21052415 - 2² = 21052411 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21052411) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5984 + ... + 8826.

It is an arithmetic number, because the mean of its divisors is an integer number (3161106).

Almost surely, 2^21052415 is an apocalyptic number.

21052415 is a deficient number, since it is larger than the sum of its proper divisors (4236433).

21052415 is a wasteful number, since it uses less digits than its factorization.

21052415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4329.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 21052415 is about 4588.2910762069. The cubic root of 21052415 is about 276.1217650426.

Adding to 21052415 its reverse (51425012), we get a palindrome (72477427).

It can be divided in two parts, 210 and 52415, that added together give a palindrome (52625).

The spelling of 21052415 in words is "twenty-one million, fifty-two thousand, four hundred fifteen".