21686142 has 16 divisors (see below), whose sum is σ = 44868240. Its totient is φ = 6979392.

The previous prime is 21686123. The next prime is 21686177. The reversal of 21686142 is 24168612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62143 + ... + 62490.

It is an arithmetic number, because the mean of its divisors is an integer number (2804265).

Almost surely, 2^21686142 is an apocalyptic number.

21686142 is an abundant number, since it is smaller than the sum of its proper divisors (23182098).

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

21686142 is a wasteful number, since it uses less digits than its factorization.

21686142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124667.

The product of its digits is 4608, while the sum is 30.

The square root of 21686142 is about 4656.8381977475. The cubic root of 21686142 is about 278.8650572366.

The spelling of 21686142 in words is "twenty-one million, six hundred eighty-six thousand, one hundred forty-two".