20999894 has 4 divisors (see below), whose sum is σ = 31499844. Its totient is φ = 10499946.

The previous prime is 20999893. The next prime is 20999899. The reversal of 20999894 is 49899902.

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

It is a super-2 number, since 2×20999894² = 881991096022472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20999893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5249972 + ... + 5249975.

It is an arithmetic number, because the mean of its divisors is an integer number (7874961).

Almost surely, 2^20999894 is an apocalyptic number.

20999894 is a deficient number, since it is larger than the sum of its proper divisors (10499950).

20999894 is a wasteful number, since it uses less digits than its factorization.

20999894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10499949.

The product of its (nonzero) digits is 419904, while the sum is 50.

The square root of 20999894 is about 4582.5641293931. The cubic root of 20999894 is about 275.8919534374.

The spelling of 20999894 in words is "twenty million, nine hundred ninety-nine thousand, eight hundred ninety-four".