21152415 has 16 divisors (see below), whose sum is σ = 35625600. Its totient is φ = 10687392.

The previous prime is 21152413. The next prime is 21152423. The reversal of 21152415 is 51425112.

It is not a de Polignac number, because 21152415 - 2¹ = 21152413 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21152391 and 21152400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152413) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36825 + ... + 37394.

It is an arithmetic number, because the mean of its divisors is an integer number (2226600).

Almost surely, 2^21152415 is an apocalyptic number.

21152415 is a deficient number, since it is larger than the sum of its proper divisors (14473185).

21152415 is a wasteful number, since it uses less digits than its factorization.

21152415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74246.

The product of its digits is 400, while the sum is 21.

The square root of 21152415 is about 4599.1754695815. The cubic root of 21152415 is about 276.5582719198.

Adding to 21152415 its reverse (51425112), we get a palindrome (72577527).

The spelling of 21152415 in words is "twenty-one million, one hundred fifty-two thousand, four hundred fifteen".