21142870 has 32 divisors (see below), whose sum is σ = 43665408. Its totient is φ = 7220448.

The previous prime is 21142867. The next prime is 21142871. The reversal of 21142870 is 7824112.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142871) 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, 25279 + ... + 26101.

It is an arithmetic number, because the mean of its divisors is an integer number (1364544).

Almost surely, 2^21142870 is an apocalyptic number.

21142870 is an abundant number, since it is smaller than the sum of its proper divisors (22522538).

21142870 is a wasteful number, since it uses less digits than its factorization.

21142870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1204.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 21142870 is about 4598.1376664906. The cubic root of 21142870 is about 276.5166668065.

Adding to 21142870 its reverse (7824112), we get a palindrome (28966982).

The spelling of 21142870 in words is "twenty-one million, one hundred forty-two thousand, eight hundred seventy".