21695406 has 16 divisors (see below), whose sum is σ = 43821648. Its totient is φ = 7160000.

The previous prime is 21695389. The next prime is 21695407. The reversal of 21695406 is 60459612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21695407) 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 7 ways as a sum of consecutive naturals, for example, 17295 + ... + 18506.

It is an arithmetic number, because the mean of its divisors is an integer number (2738853).

Almost surely, 2^21695406 is an apocalyptic number.

21695406 is an abundant number, since it is smaller than the sum of its proper divisors (22126242).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21695406 is a wasteful number, since it uses less digits than its factorization.

21695406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35907.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 21695406 is about 4657.8327578392. The cubic root of 21695406 is about 278.9047605967.

The spelling of 21695406 in words is "twenty-one million, six hundred ninety-five thousand, four hundred six".