21077506905840 has 2400 divisors, whose sum is σ = 97758718041600. Its totient is φ = 4155864330240.

The previous prime is 21077506905803. The next prime is 21077506905853. The reversal of 21077506905840 is 4850960577012.

21077506905840 is a `hidden beast` number, since 2 + 1 + 0 + 7 + 7 + 50 + 6 + 9 + 0 + 584 + 0 = 666.

It is a super-2 number, since 2×21077506905840² (a number of 27 digits) contains 22 as substring.

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 479 ways as a sum of consecutive naturals, for example, 5976042157 + ... + 5976045683.

It is an arithmetic number, because the mean of its divisors is an integer number (40732799184).

Almost surely, 2^{21077506905840} is an apocalyptic number.

21077506905840 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 21077506905840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48879359020800).

21077506905840 is an abundant number, since it is smaller than the sum of its proper divisors (76681211135760).

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

21077506905840 is a wasteful number, since it uses less digits than its factorization.

21077506905840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3665 (or 3643 counting only the distinct ones).

The product of its (nonzero) digits is 4233600, while the sum is 54.

The spelling of 21077506905840 in words is "twenty-one trillion, seventy-seven billion, five hundred six million, nine hundred five thousand, eight hundred forty".