20857290 has 16 divisors (see below), whose sum is σ = 50057568. Its totient is φ = 5561936.

The previous prime is 20857247. The next prime is 20857313. The reversal of 20857290 is 9275802.

It is a super-2 number, since 2×20857290² = 870053092288200, which contains 22 as substring.

It is a Curzon 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, 347592 + ... + 347651.

It is an arithmetic number, because the mean of its divisors is an integer number (3128598).

Almost surely, 2^20857290 is an apocalyptic number.

20857290 is an abundant number, since it is smaller than the sum of its proper divisors (29200278).

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

20857290 is a wasteful number, since it uses less digits than its factorization.

20857290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 695253.

The product of its (nonzero) digits is 10080, while the sum is 33.

The square root of 20857290 is about 4566.9782132171. The cubic root of 20857290 is about 275.2660345666.

The spelling of 20857290 in words is "twenty million, eight hundred fifty-seven thousand, two hundred ninety".