21132406 has 8 divisors (see below), whose sum is σ = 31743504. Its totient is φ = 10551240.

The previous prime is 21132383. The next prime is 21132481. The reversal of 21132406 is 60423112.

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

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, 5625 + ... + 8596.

It is an arithmetic number, because the mean of its divisors is an integer number (3967938).

Almost surely, 2^21132406 is an apocalyptic number.

21132406 is a deficient number, since it is larger than the sum of its proper divisors (10611098).

21132406 is a wasteful number, since it uses less digits than its factorization.

21132406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14966.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21132406 is about 4596.9996737002. Note that the first 3 decimals coincide. The cubic root of 21132406 is about 276.4710415299.

Adding to 21132406 its reverse (60423112), we get a palindrome (81555518).

The spelling of 21132406 in words is "twenty-one million, one hundred thirty-two thousand, four hundred six".