20155205500 has 24 divisors (see below), whose sum is σ = 44018969904. Its totient is φ = 8062082000.

The previous prime is 20155205467. The next prime is 20155205501. The reversal of 20155205500 is 550255102.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20155205501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20154706 + ... + 20155705.

It is an arithmetic number, because the mean of its divisors is an integer number (1834123746).

Almost surely, 2^20155205500 is an apocalyptic number.

20155205500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20155205500 is an abundant number, since it is smaller than the sum of its proper divisors (23863764404).

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

20155205500 is a wasteful number, since it uses less digits than its factorization.

20155205500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40310430 (or 40310418 counting only the distinct ones).

The product of its (nonzero) digits is 2500, while the sum is 25.

The spelling of 20155205500 in words is "twenty billion, one hundred fifty-five million, two hundred five thousand, five hundred".