20551544400 has 120 divisors (see below), whose sum is σ = 65897076960. Its totient is φ = 5475115520.

The previous prime is 20551544369. The next prime is 20551544473. The reversal of 20551544400 is 444515502.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1323079 + ... + 1338521.

It is an arithmetic number, because the mean of its divisors is an integer number (549142308).

Almost surely, 2^20551544400 is an apocalyptic number.

20551544400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20551544400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32948538480).

20551544400 is an abundant number, since it is smaller than the sum of its proper divisors (45345532560).

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

20551544400 is a wasteful number, since it uses less digits than its factorization.

20551544400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16573 (or 16562 counting only the distinct ones).

The product of its (nonzero) digits is 16000, while the sum is 30.

The spelling of 20551544400 in words is "twenty billion, five hundred fifty-one million, five hundred forty-four thousand, four hundred".