21378441600 has 144 divisors (see below), whose sum is σ = 76283281620. Its totient is φ = 5700910080.

The previous prime is 21378441599. The next prime is 21378441607. The reversal of 21378441600 is 614487312.

21378441600 is a `hidden beast` number, since 2 + 1 + 3 + 7 + 8 + 4 + 41 + 600 = 666.

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

It is a super-2 number, since 2×21378441600² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21378441607) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 342354 + ... + 399953.

Almost surely, 2^21378441600 is an apocalyptic number.

21378441600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21378441600 is an abundant number, since it is smaller than the sum of its proper divisors (54904840020).

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

21378441600 is a wasteful number, since it uses less digits than its factorization.

21378441600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 742337 (or 742317 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The spelling of 21378441600 in words is "twenty-one billion, three hundred seventy-eight million, four hundred forty-one thousand, six hundred".