21791894 has 4 divisors (see below), whose sum is σ = 32687844. Its totient is φ = 10895946.

The previous prime is 21791881. The next prime is 21791897. The reversal of 21791894 is 49819712.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21791897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5447972 + ... + 5447975.

It is an arithmetic number, because the mean of its divisors is an integer number (8171961).

Almost surely, 2^21791894 is an apocalyptic number.

21791894 is a deficient number, since it is larger than the sum of its proper divisors (10895950).

21791894 is a wasteful number, since it uses less digits than its factorization.

21791894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10895949.

The product of its digits is 36288, while the sum is 41.

The square root of 21791894 is about 4668.1788740364. The cubic root of 21791894 is about 279.3176155313.

The spelling of 21791894 in words is "twenty-one million, seven hundred ninety-one thousand, eight hundred ninety-four".