21286342 has 32 divisors (see below), whose sum is σ = 40032000. Its totient is φ = 8246880.

The previous prime is 21286303. The next prime is 21286351. The reversal of 21286342 is 24368212.

It is a self number, because there is not a number n which added to its sum of digits gives 21286342.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42409 + ... + 42907.

It is an arithmetic number, because the mean of its divisors is an integer number (1251000).

Almost surely, 2^21286342 is an apocalyptic number.

21286342 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21286342 is a deficient number, since it is larger than the sum of its proper divisors (18745658).

21286342 is a wasteful number, since it uses less digits than its factorization.

21286342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 796.

The product of its digits is 4608, while the sum is 28.

The square root of 21286342 is about 4613.7123880884. The cubic root of 21286342 is about 277.1407227212.

The spelling of 21286342 in words is "twenty-one million, two hundred eighty-six thousand, three hundred forty-two".