21402115 has 16 divisors (see below), whose sum is σ = 29426688. Its totient is φ = 14638176.

The previous prime is 21402109. The next prime is 21402119. The reversal of 21402115 is 51120412.

It is not a de Polignac number, because 21402115 - 2³ = 21402107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21402119) 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, 25594 + ... + 26416.

It is an arithmetic number, because the mean of its divisors is an integer number (1839168).

Almost surely, 2^21402115 is an apocalyptic number.

21402115 is a deficient number, since it is larger than the sum of its proper divisors (8024573).

21402115 is an equidigital number, since it uses as much as digits as its factorization.

21402115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1578.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 21402115 is about 4626.2419953997. The cubic root of 21402115 is about 277.6422558777.

Adding to 21402115 its reverse (51120412), we get a palindrome (72522527).

The spelling of 21402115 in words is "twenty-one million, four hundred two thousand, one hundred fifteen".