21700551 has 8 divisors (see below), whose sum is σ = 30636144. Its totient is φ = 13616000.

The previous prime is 21700531. The next prime is 21700559. The reversal of 21700551 is 15500712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21700551 - 2⁹ = 21700039 is a prime.

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 7 ways as a sum of consecutive naturals, for example, 212700 + ... + 212801.

It is an arithmetic number, because the mean of its divisors is an integer number (3829518).

Almost surely, 2^21700551 is an apocalyptic number.

21700551 is a deficient number, since it is larger than the sum of its proper divisors (8935593).

21700551 is a wasteful number, since it uses less digits than its factorization.

21700551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425521.

The product of its (nonzero) digits is 350, while the sum is 21.

The square root of 21700551 is about 4658.3850205839. The cubic root of 21700551 is about 278.9268059946.

The spelling of 21700551 in words is "twenty-one million, seven hundred thousand, five hundred fifty-one".