21700842 has 16 divisors (see below), whose sum is σ = 43669920. Its totient is φ = 7188912.

The previous prime is 21700841. The next prime is 21700843. The reversal of 21700842 is 24800712.

It is an interprime number because it is at equal distance from previous prime (21700841) and next prime (21700843).

It is not an unprimeable number, because it can be changed into a prime (21700841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10117 + ... + 12072.

It is an arithmetic number, because the mean of its divisors is an integer number (2729370).

Almost surely, 2^21700842 is an apocalyptic number.

21700842 is an abundant number, since it is smaller than the sum of its proper divisors (21969078).

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

21700842 is a wasteful number, since it uses less digits than its factorization.

21700842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22357.

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 21700842 is about 4658.4162544796. The cubic root of 21700842 is about 278.9280527731.

The spelling of 21700842 in words is "twenty-one million, seven hundred thousand, eight hundred forty-two".