21553694 has 4 divisors (see below), whose sum is σ = 32330544. Its totient is φ = 10776846.

The previous prime is 21553643. The next prime is 21553717. The reversal of 21553694 is 49635512.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5388422 + ... + 5388425.

It is an arithmetic number, because the mean of its divisors is an integer number (8082636).

Almost surely, 2^21553694 is an apocalyptic number.

21553694 is a deficient number, since it is larger than the sum of its proper divisors (10776850).

21553694 is a wasteful number, since it uses less digits than its factorization.

21553694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10776849.

The product of its digits is 32400, while the sum is 35.

The square root of 21553694 is about 4642.5956102163. The cubic root of 21553694 is about 278.2961752141.

The spelling of 21553694 in words is "twenty-one million, five hundred fifty-three thousand, six hundred ninety-four".