21700550 has 12 divisors (see below), whose sum is σ = 40363116. Its totient is φ = 8680200.

The previous prime is 21700531. The next prime is 21700559. The reversal of 21700550 is 5500712.

It is a hoax number, since the sum of its digits (20) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21700559) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 216956 + ... + 217055.

It is an arithmetic number, because the mean of its divisors is an integer number (3363593).

Almost surely, 2^21700550 is an apocalyptic number.

21700550 is a deficient number, since it is larger than the sum of its proper divisors (18662566).

21700550 is a wasteful number, since it uses less digits than its factorization.

21700550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434023 (or 434018 counting only the distinct ones).

The product of its (nonzero) digits is 350, while the sum is 20.

The square root of 21700550 is about 4658.3849132505. The cubic root of 21700550 is about 278.9268017101.

The spelling of 21700550 in words is "twenty-one million, seven hundred thousand, five hundred fifty".