21917770 has 32 divisors (see below), whose sum is σ = 45266688. Its totient is φ = 7484928.

The previous prime is 21917767. The next prime is 21917783. The reversal of 21917770 is 7771912.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24267 + ... + 25153.

It is an arithmetic number, because the mean of its divisors is an integer number (1414584).

Almost surely, 2^21917770 is an apocalyptic number.

21917770 is an abundant number, since it is smaller than the sum of its proper divisors (23348918).

21917770 is a wasteful number, since it uses less digits than its factorization.

21917770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1254.

The product of its (nonzero) digits is 6174, while the sum is 34.

The square root of 21917770 is about 4681.6418060334. The cubic root of 21917770 is about 279.8543885750.

The spelling of 21917770 in words is "twenty-one million, nine hundred seventeen thousand, seven hundred seventy".