21702018 has 32 divisors (see below), whose sum is σ = 48779136. Its totient is φ = 6386688.

The previous prime is 21702001. The next prime is 21702049. The reversal of 21702018 is 81020712.

It is a junction number, because it is equal to n+sod(n) for n = 21701985 and 21702003.

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, 4255 + ... + 7842.

It is an arithmetic number, because the mean of its divisors is an integer number (1524348).

Almost surely, 2^21702018 is an apocalyptic number.

21702018 is an abundant number, since it is smaller than the sum of its proper divisors (27077118).

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

21702018 is a wasteful number, since it uses less digits than its factorization.

21702018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12138.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 21702018 is about 4658.5424759253. The cubic root of 21702018 is about 278.9330911869.

The spelling of 21702018 in words is "twenty-one million, seven hundred two thousand, eighteen".