21402213 has 32 divisors (see below), whose sum is σ = 34553856. Its totient is φ = 11518848.

The previous prime is 21402209. The next prime is 21402217. The reversal of 21402213 is 31220412.

It is an interprime number because it is at equal distance from previous prime (21402209) and next prime (21402217).

It is not a de Polignac number, because 21402213 - 2² = 21402209 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21402192 and 21402201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402217) 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 31 ways as a sum of consecutive naturals, for example, 34956 + ... + 35562.

It is an arithmetic number, because the mean of its divisors is an integer number (1079808).

Almost surely, 2^21402213 is an apocalyptic number.

21402213 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21402213 is a deficient number, since it is larger than the sum of its proper divisors (13151643).

21402213 is a wasteful number, since it uses less digits than its factorization.

21402213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 713.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21402213 is about 4626.2525871379. The cubic root of 21402213 is about 277.6426796504.

Adding to 21402213 its reverse (31220412), we get a palindrome (52622625).

The spelling of 21402213 in words is "twenty-one million, four hundred two thousand, two hundred thirteen".