21037756740 has 384 divisors, whose sum is σ = 81236348928. Its totient is φ = 3925739520.

The previous prime is 21037756681. The next prime is 21037756741. The reversal of 21037756740 is 4765773012.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 21037756692 and 21037756701.

It is not an unprimeable number, because it can be changed into a prime (21037756741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2217487 + ... + 2226953.

It is an arithmetic number, because the mean of its divisors is an integer number (211552992).

Almost surely, 2^21037756740 is an apocalyptic number.

21037756740 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 21037756740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40618174464).

21037756740 is an abundant number, since it is smaller than the sum of its proper divisors (60198592188).

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

21037756740 is a wasteful number, since it uses less digits than its factorization.

21037756740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9547 (or 9545 counting only the distinct ones).

The product of its (nonzero) digits is 246960, while the sum is 42.

It can be divided in two parts, 21037 and 756740, that added together give a palindrome (777777).

The spelling of 21037756740 in words is "twenty-one billion, thirty-seven million, seven hundred fifty-six thousand, seven hundred forty".