21183994751 has 2 divisors, whose sum is σ = 21183994752. Its totient is φ = 21183994750.

The previous prime is 21183994723. The next prime is 21183994787. The reversal of 21183994751 is 15749938112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21183994751 - 2¹⁴ = 21183978367 is a prime.

It is a super-2 number, since 2×21183994751² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21183994751.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21183294751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10591997375 + 10591997376.

It is an arithmetic number, because the mean of its divisors is an integer number (10591997376).

Almost surely, 2^21183994751 is an apocalyptic number.

21183994751 is a deficient number, since it is larger than the sum of its proper divisors (1).

21183994751 is an equidigital number, since it uses as much as digits as its factorization.

21183994751 is an evil number, because the sum of its binary digits is even.

The product of its digits is 544320, while the sum is 50.

The spelling of 21183994751 in words is "twenty-one billion, one hundred eighty-three million, nine hundred ninety-four thousand, seven hundred fifty-one".