21420410 has 64 divisors (see below), whose sum is σ = 45636480. Its totient is φ = 7153920.

The previous prime is 21420403. The next prime is 21420433. The reversal of 21420410 is 1402412.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 77192 + ... + 77468.

It is an arithmetic number, because the mean of its divisors is an integer number (713070).

Almost surely, 2^21420410 is an apocalyptic number.

21420410 is an abundant number, since it is smaller than the sum of its proper divisors (24216070).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21420410 is a wasteful number, since it uses less digits than its factorization.

21420410 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351.

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

The square root of 21420410 is about 4628.2188798716. The cubic root of 21420410 is about 277.7213449212.

Adding to 21420410 its reverse (1402412), we get a palindrome (22822822).

The spelling of 21420410 in words is "twenty-one million, four hundred twenty thousand, four hundred ten".