21678142 has 16 divisors (see below), whose sum is σ = 33142032. Its totient is φ = 10632960.

The previous prime is 21678133. The next prime is 21678143. The reversal of 21678142 is 24187612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21678143) 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, 24988 + ... + 25840.

It is an arithmetic number, because the mean of its divisors is an integer number (2071377).

Almost surely, 2^21678142 is an apocalyptic number.

21678142 is a deficient number, since it is larger than the sum of its proper divisors (11463890).

21678142 is a wasteful number, since it uses less digits than its factorization.

21678142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1083.

The product of its digits is 5376, while the sum is 31.

The square root of 21678142 is about 4655.9791666201. The cubic root of 21678142 is about 278.8307619888.

The spelling of 21678142 in words is "twenty-one million, six hundred seventy-eight thousand, one hundred forty-two".