20400405502 has 4 divisors (see below), whose sum is σ = 30600608256. Its totient is φ = 10200202750.

The previous prime is 20400405481. The next prime is 20400405503. The reversal of 20400405502 is 20550400402.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20400405503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5100101374 + ... + 5100101377.

It is an arithmetic number, because the mean of its divisors is an integer number (7650152064).

Almost surely, 2^20400405502 is an apocalyptic number.

20400405502 is a deficient number, since it is larger than the sum of its proper divisors (10200202754).

20400405502 is a wasteful number, since it uses less digits than its factorization.

20400405502 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10200202753.

The product of its (nonzero) digits is 1600, while the sum is 22.

Adding to 20400405502 its reverse (20550400402), we get a palindrome (40950805904).

The spelling of 20400405502 in words is "twenty billion, four hundred million, four hundred five thousand, five hundred two".