21425670 has 96 divisors (see below), whose sum is σ = 64696320. Its totient is φ = 4818240.

The previous prime is 21425659. The next prime is 21425671. The reversal of 21425670 is 7652412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21425671) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 44491 + ... + 44969.

It is an arithmetic number, because the mean of its divisors is an integer number (673920).

Almost surely, 2^21425670 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21425670, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32348160).

21425670 is an abundant number, since it is smaller than the sum of its proper divisors (43270650).

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

21425670 is a wasteful number, since it uses less digits than its factorization.

21425670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570 (or 567 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21425670 is about 4628.7870981500. The cubic root of 21425670 is about 277.7440754963.

The spelling of 21425670 in words is "twenty-one million, four hundred twenty-five thousand, six hundred seventy".