21701970 has 96 divisors (see below), whose sum is σ = 59192640. Its totient is φ = 5512320.

The previous prime is 21701959. The next prime is 21701987. The reversal of 21701970 is 7910712.

It is a congruent number.

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 47 ways as a sum of consecutive naturals, for example, 323877 + ... + 323943.

It is an arithmetic number, because the mean of its divisors is an integer number (616590).

Almost surely, 2^21701970 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21701970, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29596320).

21701970 is an abundant number, since it is smaller than the sum of its proper divisors (37490670).

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

21701970 is a wasteful number, since it uses less digits than its factorization.

21701970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200 (or 197 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

The square root of 21701970 is about 4658.5373240965. The cubic root of 21701970 is about 278.9328855409.

The spelling of 21701970 in words is "twenty-one million, seven hundred one thousand, nine hundred seventy".