21400210 has 16 divisors (see below), whose sum is σ = 41483736. Its totient is φ = 7901568.

The previous prime is 21400201. The next prime is 21400217. The reversal of 21400210 is 1200412.

It can be written as a sum of positive squares in 4 ways, for example, as 14676561 + 6723649 = 3831^2 + 2593^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21400217) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82179 + ... + 82438.

Almost surely, 2^21400210 is an apocalyptic number.

21400210 is a deficient number, since it is larger than the sum of its proper divisors (20083526).

21400210 is a wasteful number, since it uses less digits than its factorization.

21400210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164637.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 21400210 is about 4626.0361001618. The cubic root of 21400210 is about 277.6340179973.

Adding to 21400210 its reverse (1200412), we get a palindrome (22600622).

The spelling of 21400210 in words is "twenty-one million, four hundred thousand, two hundred ten".