21710172 has 24 divisors (see below), whose sum is σ = 55262592. Its totient is φ = 6578800.

The previous prime is 21710159. The next prime is 21710177. The reversal of 21710172 is 27101712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21710177) 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, 82104 + ... + 82367.

It is an arithmetic number, because the mean of its divisors is an integer number (2302608).

Almost surely, 2^21710172 is an apocalyptic number.

21710172 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21710172 is an abundant number, since it is smaller than the sum of its proper divisors (33552420).

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

21710172 is a wasteful number, since it uses less digits than its factorization.

21710172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164489 (or 164487 counting only the distinct ones).

The product of its (nonzero) digits is 196, while the sum is 21.

The square root of 21710172 is about 4659.4175601678. The cubic root of 21710172 is about 278.9680208976.

Adding to 21710172 its reverse (27101712), we get a palindrome (48811884).

The spelling of 21710172 in words is "twenty-one million, seven hundred ten thousand, one hundred seventy-two".