20406502 has 4 divisors (see below), whose sum is σ = 30609756. Its totient is φ = 10203250.

The previous prime is 20406461. The next prime is 20406521. The reversal of 20406502 is 20560402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 20560402 = 2 ⋅10280201.

It is a self number, because there is not a number n which added to its sum of digits gives 20406502.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5101624 + ... + 5101627.

It is an arithmetic number, because the mean of its divisors is an integer number (7652439).

Almost surely, 2^20406502 is an apocalyptic number.

20406502 is a deficient number, since it is larger than the sum of its proper divisors (10203254).

20406502 is a wasteful number, since it uses less digits than its factorization.

20406502 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10203253.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 20406502 is about 4517.3556424085. The cubic root of 20406502 is about 273.2684679842.

Adding to 20406502 its reverse (20560402), we get a palindrome (40966904).

The spelling of 20406502 in words is "twenty million, four hundred six thousand, five hundred two".