20490261 has 24 divisors (see below), whose sum is σ = 30694272. Its totient is φ = 12144000.

The previous prime is 20490257. The next prime is 20490271. The reversal of 20490261 is 16209402.

It is not a de Polignac number, because 20490261 - 2² = 20490257 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20490251) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16461 + ... + 17661.

It is an arithmetic number, because the mean of its divisors is an integer number (1278928).

Almost surely, 2^20490261 is an apocalyptic number.

It is an amenable number.

20490261 is a deficient number, since it is larger than the sum of its proper divisors (10204011).

20490261 is a wasteful number, since it uses less digits than its factorization.

20490261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273 (or 1262 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 20490261 is about 4526.6169486715. The cubic root of 20490261 is about 273.6418367122.

Adding to 20490261 its reverse (16209402), we get a palindrome (36699663).

The spelling of 20490261 in words is "twenty million, four hundred ninety thousand, two hundred sixty-one".