21965606 has 16 divisors (see below), whose sum is σ = 35700000. Its totient is φ = 10135944.

The previous prime is 21965599. The next prime is 21965623. The reversal of 21965606 is 60656912.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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, 1895 + ... + 6893.

It is an arithmetic number, because the mean of its divisors is an integer number (2231250).

Almost surely, 2^21965606 is an apocalyptic number.

21965606 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21965606 is a deficient number, since it is larger than the sum of its proper divisors (13734394).

21965606 is an equidigital number, since it uses as much as digits as its factorization.

21965606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5040 (or 5014 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 21965606 is about 4686.7479129989. The cubic root of 21965606 is about 280.0578366919.

The spelling of 21965606 in words is "twenty-one million, nine hundred sixty-five thousand, six hundred six".