21016454400 has 540 divisors, whose sum is σ = 78939885024. Its totient is φ = 5515776000.

The previous prime is 21016454377. The next prime is 21016454423. The reversal of 21016454400 is 445461012.

21016454400 is a `hidden beast` number, since 2 + 10 + 1 + 645 + 4 + 4 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21016454377) and next prime (21016454423).

It is a tau number, because it is divible by the number of its divisors (540).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 36806115 + ... + 36806685.

Almost surely, 2^21016454400 is an apocalyptic number.

21016454400 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 21016454400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39469942512).

21016454400 is an abundant number, since it is smaller than the sum of its proper divisors (57923430624).

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

21016454400 is an equidigital number, since it uses as much as digits as its factorization.

21016454400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680 (or 652 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The spelling of 21016454400 in words is "twenty-one billion, sixteen million, four hundred fifty-four thousand, four hundred".