20657290 has 8 divisors (see below), whose sum is σ = 37183140. Its totient is φ = 8262912.

The previous prime is 20657281. The next prime is 20657293. The reversal of 20657290 is 9275602.

It can be written as a sum of positive squares in 2 ways, for example, as 20223009 + 434281 = 4497^2 + 659^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-3 number, since 3×20657290³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (20657293) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1032855 + ... + 1032874.

Almost surely, 2^20657290 is an apocalyptic number.

20657290 is a deficient number, since it is larger than the sum of its proper divisors (16525850).

20657290 is a wasteful number, since it uses less digits than its factorization.

20657290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2065736.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 20657290 is about 4545.0291528218. The cubic root of 20657290 is about 274.3833676705.

The spelling of 20657290 in words is "twenty million, six hundred fifty-seven thousand, two hundred ninety".