21171370 has 24 divisors (see below), whose sum is σ = 41890212. Its totient is φ = 7698240.

The previous prime is 21171361. The next prime is 21171373. The reversal of 21171370 is 7317112.

It can be written as a sum of positive squares in 2 ways, for example, as 17380561 + 3790809 = 4169^2 + 1947^2 .

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (21171373) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7539 + ... + 9958.

Almost surely, 2^21171370 is an apocalyptic number.

21171370 is a deficient number, since it is larger than the sum of its proper divisors (20718842).

21171370 is a wasteful number, since it uses less digits than its factorization.

21171370 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17526 (or 17515 counting only the distinct ones).

The product of its (nonzero) digits is 294, while the sum is 22.

The square root of 21171370 is about 4601.2357035909. The cubic root of 21171370 is about 276.6408566107.

Adding to 21171370 its reverse (7317112), we get a palindrome (28488482).

The spelling of 21171370 in words is "twenty-one million, one hundred seventy-one thousand, three hundred seventy".