21374585856 has 440 divisors, whose sum is σ = 70489738704. Its totient is φ = 6409912320.

The previous prime is 21374585831. The next prime is 21374585891. The reversal of 21374585856 is 65858547312.

21374585856 is a `hidden beast` number, since 2 + 1 + 3 + 7 + 4 + 58 + 585 + 6 = 666.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 46365466 + ... + 46365926.

Almost surely, 2^21374585856 is an apocalyptic number.

21374585856 is a gapful number since it is divisible by the number (26) 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 21374585856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35244869352).

21374585856 is an abundant number, since it is smaller than the sum of its proper divisors (49115152848).

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

21374585856 is a wasteful number, since it uses less digits than its factorization.

21374585856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549 (or 522 counting only the distinct ones).

The product of its digits is 8064000, while the sum is 54.

The spelling of 21374585856 in words is "twenty-one billion, three hundred seventy-four million, five hundred eighty-five thousand, eight hundred fifty-six".