21052406 has 8 divisors (see below), whose sum is σ = 32951664. Its totient is φ = 10068520.

The previous prime is 21052391. The next prime is 21052411. The reversal of 21052406 is 60425012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 228785 + ... + 228876.

It is an arithmetic number, because the mean of its divisors is an integer number (4118958).

Almost surely, 2^21052406 is an apocalyptic number.

21052406 is a deficient number, since it is larger than the sum of its proper divisors (11899258).

21052406 is a wasteful number, since it uses less digits than its factorization.

21052406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457686.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21052406 is about 4588.2900954495. The cubic root of 21052406 is about 276.1217256949.

Adding to 21052406 its reverse (60425012), we get a palindrome (81477418).

The spelling of 21052406 in words is "twenty-one million, fifty-two thousand, four hundred six".