21553394 has 8 divisors (see below), whose sum is σ = 32616540. Its totient is φ = 10681216.

The previous prime is 21553393. The next prime is 21553403. The reversal of 21553394 is 49335512.

It can be written as a sum of positive squares in 2 ways, for example, as 14922769 + 6630625 = 3863^2 + 2575^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21553394.

It is not an unprimeable number, because it can be changed into a prime (21553393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47459 + ... + 47910.

Almost surely, 2^21553394 is an apocalyptic number.

21553394 is a deficient number, since it is larger than the sum of its proper divisors (11063146).

21553394 is a wasteful number, since it uses less digits than its factorization.

21553394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95484.

The product of its digits is 16200, while the sum is 32.

The square root of 21553394 is about 4642.5633005916. The cubic root of 21553394 is about 278.2948840319.

The spelling of 21553394 in words is "twenty-one million, five hundred fifty-three thousand, three hundred ninety-four".