21331807742747 has 2 divisors, whose sum is σ = 21331807742748. Its totient is φ = 21331807742746.

The previous prime is 21331807742699. The next prime is 21331807742789. The reversal of 21331807742747 is 74724770813312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21331807742747 - 2¹⁰ = 21331807741723 is a prime.

It is a super-2 number, since 2×21331807742747² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21331807742692 and 21331807742701.

It is not a weakly prime, because it can be changed into another prime (21331707742747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665903871373 + 10665903871374.

It is an arithmetic number, because the mean of its divisors is an integer number (10665903871374).

Almost surely, 2^{21331807742747} is an apocalyptic number.

21331807742747 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331807742747 is an equidigital number, since it uses as much as digits as its factorization.

21331807742747 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11063808, while the sum is 56.

The spelling of 21331807742747 in words is "twenty-one trillion, three hundred thirty-one billion, eight hundred seven million, seven hundred forty-two thousand, seven hundred forty-seven".