21171670 has 16 divisors (see below), whose sum is σ = 41040720. Its totient is φ = 7817184.

The previous prime is 21171649. The next prime is 21171671. The reversal of 21171670 is 7617112.

It is a super-2 number, since 2×21171670² = 896479221177800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21171671) 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, 81300 + ... + 81559.

It is an arithmetic number, because the mean of its divisors is an integer number (2565045).

Almost surely, 2^21171670 is an apocalyptic number.

21171670 is a deficient number, since it is larger than the sum of its proper divisors (19869050).

21171670 is a wasteful number, since it uses less digits than its factorization.

21171670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162879.

The product of its (nonzero) digits is 588, while the sum is 25.

The square root of 21171670 is about 4601.2683034137. The cubic root of 21171670 is about 276.6421632788.

Adding to 21171670 its reverse (7617112), we get a palindrome (28788782).

The spelling of 21171670 in words is "twenty-one million, one hundred seventy-one thousand, six hundred seventy".