21740253066 has 240 divisors, whose sum is σ = 58922642688. Its totient is φ = 6001128000.

The previous prime is 21740253061. The next prime is 21740253103. The reversal of 21740253066 is 66035204712.

21740253066 is a `hidden beast` number, since 21 + 7 + 40 + 2 + 530 + 66 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21740253066.

It is not an unprimeable number, because it can be changed into a prime (21740253061) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 36173166 + ... + 36173766.

Almost surely, 2^21740253066 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21740253066, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29461321344).

21740253066 is an abundant number, since it is smaller than the sum of its proper divisors (37182389622).

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

21740253066 is an frugal number, since it uses more digits than its factorization.

21740253066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 677 (or 644 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

Adding to 21740253066 its reverse (66035204712), we get a palindrome (87775457778).

The spelling of 21740253066 in words is "twenty-one billion, seven hundred forty million, two hundred fifty-three thousand, sixty-six".