21051415 has 16 divisors (see below), whose sum is σ = 31495680. Its totient is φ = 13122720.

The previous prime is 21051403. The next prime is 21051421. The reversal of 21051415 is 51415012.

It is not a de Polignac number, because 21051415 - 2⁵ = 21051383 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21051392 and 21051401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26955 + ... + 27724.

It is an arithmetic number, because the mean of its divisors is an integer number (1968480).

Almost surely, 2^21051415 is an apocalyptic number.

21051415 is a deficient number, since it is larger than the sum of its proper divisors (10444265).

21051415 is a wasteful number, since it uses less digits than its factorization.

21051415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54702.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 21051415 is about 4588.1821018787. The cubic root of 21051415 is about 276.1173930005.

Adding to 21051415 its reverse (51415012), we get a palindrome (72466427).

The spelling of 21051415 in words is "twenty-one million, fifty-one thousand, four hundred fifteen".