20400220400 has 120 divisors (see below), whose sum is σ = 56324040864. Its totient is φ = 6955545600.

The previous prime is 20400220387. The next prime is 20400220427. The reversal of 20400220400 is 402200402.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (14).

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, 486674 + ... + 526926.

Almost surely, 2^20400220400 is an apocalyptic number.

20400220400 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 20400220400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28162020432).

20400220400 is an abundant number, since it is smaller than the sum of its proper divisors (35923820464).

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

20400220400 is a wasteful number, since it uses less digits than its factorization.

20400220400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40459 (or 40448 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 14.

Adding to 20400220400 its reverse (402200402), we get a palindrome (20802420802).

The spelling of 20400220400 in words is "twenty billion, four hundred million, two hundred twenty thousand, four hundred".