21694955 has 16 divisors (see below), whose sum is σ = 26810784. Its totient is φ = 16846080.

The previous prime is 21694951. The next prime is 21694991. The reversal of 21694955 is 55949612.

It is not a de Polignac number, because 21694955 - 2² = 21694951 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21694951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24887 + ... + 25743.

It is an arithmetic number, because the mean of its divisors is an integer number (1675674).

Almost surely, 2^21694955 is an apocalyptic number.

21694955 is a deficient number, since it is larger than the sum of its proper divisors (5115829).

21694955 is an equidigital number, since it uses as much as digits as its factorization.

21694955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1006.

The product of its digits is 97200, while the sum is 41.

The square root of 21694955 is about 4657.7843445140. The cubic root of 21694955 is about 278.9028279768.

The spelling of 21694955 in words is "twenty-one million, six hundred ninety-four thousand, nine hundred fifty-five".