20505402 has 24 divisors (see below), whose sum is σ = 44647200. Its totient is φ = 6801480.

The previous prime is 20505379. The next prime is 20505409. The reversal of 20505402 is 20450502.

It is a super-2 number, since 2×20505402² = 840943022363208, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (20505409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1099 + ... + 6497.

It is an arithmetic number, because the mean of its divisors is an integer number (1860300).

Almost surely, 2^20505402 is an apocalyptic number.

20505402 is an abundant number, since it is smaller than the sum of its proper divisors (24141798).

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

20505402 is a wasteful number, since it uses less digits than its factorization.

20505402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5618 (or 5615 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 18.

The square root of 20505402 is about 4528.2890808781. The cubic root of 20505402 is about 273.7092214232.

Adding to 20505402 its reverse (20450502), we get a palindrome (40955904).

The spelling of 20505402 in words is "twenty million, five hundred five thousand, four hundred two".