21402410 has 16 divisors (see below), whose sum is σ = 39464712. Its totient is φ = 8352000.

The previous prime is 21402401. The next prime is 21402419. The reversal of 21402410 is 1420412.

It is an interprime number because it is at equal distance from previous prime (21402401) and next prime (21402419).

It can be written as a sum of positive squares in 4 ways, for example, as 15531481 + 5870929 = 3941^2 + 2423^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21402419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25691 + ... + 26510.

Almost surely, 2^21402410 is an apocalyptic number.

21402410 is a deficient number, since it is larger than the sum of its proper divisors (18062302).

21402410 is a wasteful number, since it uses less digits than its factorization.

21402410 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52249.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21402410 is about 4626.2738786198. The cubic root of 21402410 is about 277.6435315162.

Adding to 21402410 its reverse (1420412), we get a palindrome (22822822).

It can be divided in two parts, 21402 and 410, that added together give a palindrome (21812).

The spelling of 21402410 in words is "twenty-one million, four hundred two thousand, four hundred ten".