21701660 has 24 divisors (see below), whose sum is σ = 45677520. Its totient is φ = 8660864.

The previous prime is 21701651. The next prime is 21701683. The reversal of 21701660 is 6610712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10427 + ... + 12333.

It is an arithmetic number, because the mean of its divisors is an integer number (1903230).

Almost surely, 2^21701660 is an apocalyptic number.

21701660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21701660 is an abundant number, since it is smaller than the sum of its proper divisors (23975860).

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

21701660 is a wasteful number, since it uses less digits than its factorization.

21701660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2485 (or 2483 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 21701660 is about 4658.5040517316. The cubic root of 21701660 is about 278.9315574033.

The spelling of 21701660 in words is "twenty-one million, seven hundred one thousand, six hundred sixty".