21621446 has 48 divisors (see below), whose sum is σ = 42550272. Its totient is φ = 8139600.

The previous prime is 21621437. The next prime is 21621463. The reversal of 21621446 is 64412612.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33095 + ... + 33741.

It is an arithmetic number, because the mean of its divisors is an integer number (886464).

Almost surely, 2^21621446 is an apocalyptic number.

21621446 is a deficient number, since it is larger than the sum of its proper divisors (20928826).

21621446 is a wasteful number, since it uses less digits than its factorization.

21621446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 705 (or 698 counting only the distinct ones).

The product of its digits is 2304, while the sum is 26.

The square root of 21621446 is about 4649.8866652855. The cubic root of 21621446 is about 278.5874694498.

The spelling of 21621446 in words is "twenty-one million, six hundred twenty-one thousand, four hundred forty-six".