21394436580 has 192 divisors, whose sum is σ = 72711475200. Its totient is φ = 5179386240.

The previous prime is 21394436533. The next prime is 21394436593. The reversal of 21394436580 is 8563449312.

21394436580 is a `hidden beast` number, since 2 + 1 + 39 + 4 + 4 + 36 + 580 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5242981 + ... + 5247059.

It is an arithmetic number, because the mean of its divisors is an integer number (378705600).

Almost surely, 2^21394436580 is an apocalyptic number.

21394436580 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 21394436580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36355737600).

21394436580 is an abundant number, since it is smaller than the sum of its proper divisors (51317038620).

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

21394436580 is a wasteful number, since it uses less digits than its factorization.

21394436580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4991 (or 4983 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The spelling of 21394436580 in words is "twenty-one billion, three hundred ninety-four million, four hundred thirty-six thousand, five hundred eighty".