21694563 has 24 divisors (see below), whose sum is σ = 34332480. Its totient is φ = 13091760.

The previous prime is 21694559. The next prime is 21694583. The reversal of 21694563 is 36549612.

It is a happy number.

21694563 is a `hidden beast` number, since 2 + 1 + 6 + 94 + 563 = 666.

It is not a de Polignac number, because 21694563 - 2² = 21694559 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21694583) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41220 + ... + 41742.

It is an arithmetic number, because the mean of its divisors is an integer number (1430520).

Almost surely, 2^21694563 is an apocalyptic number.

21694563 is a deficient number, since it is larger than the sum of its proper divisors (12637917).

21694563 is a wasteful number, since it uses less digits than its factorization.

21694563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 959 (or 956 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 21694563 is about 4657.7422642306. The cubic root of 21694563 is about 278.9011481613.

The spelling of 21694563 in words is "twenty-one million, six hundred ninety-four thousand, five hundred sixty-three".