21251435400 has 960 divisors, whose sum is σ = 86206982400. Its totient is φ = 4807434240.

The previous prime is 21251435389. The next prime is 21251435417. The reversal of 21251435400 is 453415212.

21251435400 is a `hidden beast` number, since 2 + 1 + 251 + 4 + 3 + 5 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 188065744 + ... + 188065856.

It is an arithmetic number, because the mean of its divisors is an integer number (89798940).

Almost surely, 2^21251435400 is an apocalyptic number.

21251435400 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 21251435400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43103491200).

21251435400 is an abundant number, since it is smaller than the sum of its proper divisors (64955547000).

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

21251435400 is a wasteful number, since it uses less digits than its factorization.

21251435400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220 (or 202 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The spelling of 21251435400 in words is "twenty-one billion, two hundred fifty-one million, four hundred thirty-five thousand, four hundred".