21994659 has 32 divisors (see below), whose sum is σ = 33652800. Its totient is φ = 14370048.

The previous prime is 21994657. The next prime is 21994667. The reversal of 21994659 is 95649912.

It is not a de Polignac number, because 21994659 - 2¹ = 21994657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21994657) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 194587 + ... + 194699.

It is an arithmetic number, because the mean of its divisors is an integer number (1051650).

Almost surely, 2^21994659 is an apocalyptic number.

21994659 is a deficient number, since it is larger than the sum of its proper divisors (11658141).

21994659 is an frugal number, since it uses more digits than its factorization.

21994659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223 (or 205 counting only the distinct ones).

The product of its digits is 174960, while the sum is 45.

The square root of 21994659 is about 4689.8463727504. The cubic root of 21994659 is about 280.1812559393.

The spelling of 21994659 in words is "twenty-one million, nine hundred ninety-four thousand, six hundred fifty-nine".