21018647133990 has 640 divisors, whose sum is σ = 65342241423360. Its totient is φ = 4800566476800.

The previous prime is 21018647133941. The next prime is 21018647134003. The reversal of 21018647133990 is 9933174681012.

21018647133990 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 86 + 471 + 3 + 3 + 9 + 90 = 666.

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 319 ways as a sum of consecutive naturals, for example, 2505496716 + ... + 2505505104.

It is an arithmetic number, because the mean of its divisors is an integer number (102097252224).

Almost surely, 2^{21018647133990} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21018647133990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32671120711680).

21018647133990 is an abundant number, since it is smaller than the sum of its proper divisors (44323594289370).

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

21018647133990 is a wasteful number, since it uses less digits than its factorization.

21018647133990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8690 (or 8681 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 54.

The spelling of 21018647133990 in words is "twenty-one trillion, eighteen billion, six hundred forty-seven million, one hundred thirty-three thousand, nine hundred ninety".