19400400 has 180 divisors, whose sum is σ = 71509932. Its totient is φ = 4853760.

The previous prime is 19400377. The next prime is 19400411. The reversal of 19400400 is 400491.

It can be written as a sum of positive squares in 6 ways, for example, as 1354896 + 18045504 = 1164^2 + 4248^2 .

It is a tau number, because it is divible by the number of its divisors (180).

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 polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 61042 + ... + 61358.

Almost surely, 2^19400400 is an apocalyptic number.

19400400 is a gapful number since it is divisible by the number (10) 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 19400400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35754966).

19400400 is an abundant number, since it is smaller than the sum of its proper divisors (52109532).

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

19400400 is a wasteful number, since it uses less digits than its factorization.

19400400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 358 (or 344 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 19400400 is about 4404.5885165359. The cubic root of 19400400 is about 268.7015849328.

Adding to 19400400 its reverse (400491), we get a palindrome (19800891).

The spelling of 19400400 in words is "nineteen million, four hundred thousand, four hundred".