20511122400 has 144 divisors (see below), whose sum is σ = 74181970800. Its totient is φ = 5469626880.

The previous prime is 20511122393. The next prime is 20511122473. The reversal of 20511122400 is 422111502.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×20511122400² (a number of 21 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 453195 + ... + 496394.

It is an arithmetic number, because the mean of its divisors is an integer number (515152575).

Almost surely, 2^20511122400 is an apocalyptic number.

20511122400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20511122400 is an abundant number, since it is smaller than the sum of its proper divisors (53670848400).

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

20511122400 is a wasteful number, since it uses less digits than its factorization.

20511122400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 949618 (or 949599 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

Adding to 20511122400 its reverse (422111502), we get a palindrome (20933233902).

The spelling of 20511122400 in words is "twenty billion, five hundred eleven million, one hundred twenty-two thousand, four hundred".