21917070 has 96 divisors (see below), whose sum is σ = 68590080. Its totient is φ = 4743360.

The previous prime is 21917023. The next prime is 21917113. The reversal of 21917070 is 7071912.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11055 + ... + 12885.

It is an arithmetic number, because the mean of its divisors is an integer number (714480).

Almost surely, 2^21917070 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21917070, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34295040).

21917070 is an abundant number, since it is smaller than the sum of its proper divisors (46673010).

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

21917070 is a wasteful number, since it uses less digits than its factorization.

21917070 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1870 (or 1867 counting only the distinct ones).

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

The square root of 21917070 is about 4681.5670453386. The cubic root of 21917070 is about 279.8514092549.

Adding to 21917070 its reverse (7071912), we get a palindrome (28988982).

It can be divided in two parts, 2191 and 7070, that added together give a cube (9261 = 21³).

The spelling of 21917070 in words is "twenty-one million, nine hundred seventeen thousand, seventy".