21427170 has 32 divisors (see below), whose sum is σ = 52081920. Its totient is φ = 5640960.

The previous prime is 21427141. The next prime is 21427171. The reversal of 21427170 is 7172412.

It is a super-2 number, since 2×21427170² = 918247228417800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21427170.

It is not an unprimeable number, because it can be changed into a prime (21427171) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2151 + ... + 6890.

It is an arithmetic number, because the mean of its divisors is an integer number (1627560).

Almost surely, 2^21427170 is an apocalyptic number.

21427170 is an abundant number, since it is smaller than the sum of its proper divisors (30654750).

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

21427170 is a wasteful number, since it uses less digits than its factorization.

21427170 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9130.

The product of its (nonzero) digits is 784, while the sum is 24.

The square root of 21427170 is about 4628.9491248014. The cubic root of 21427170 is about 277.7505569178.

Adding to 21427170 its reverse (7172412), we get a palindrome (28599582).

The spelling of 21427170 in words is "twenty-one million, four hundred twenty-seven thousand, one hundred seventy".