21531333313547 has 2 divisors, whose sum is σ = 21531333313548. Its totient is φ = 21531333313546.

The previous prime is 21531333313439. The next prime is 21531333313601. The reversal of 21531333313547 is 74531333313512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21531333313547 - 2¹⁶ = 21531333248011 is a prime.

It is a super-2 number, since 2×21531333313547² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21531333313498 and 21531333313507.

It is not a weakly prime, because it can be changed into another prime (21531333312547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765666656773 + 10765666656774.

It is an arithmetic number, because the mean of its divisors is an integer number (10765666656774).

Almost surely, 2^{21531333313547} is an apocalyptic number.

21531333313547 is a deficient number, since it is larger than the sum of its proper divisors (1).

21531333313547 is an equidigital number, since it uses as much as digits as its factorization.

21531333313547 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1020600, while the sum is 44.

The spelling of 21531333313547 in words is "twenty-one trillion, five hundred thirty-one billion, three hundred thirty-three million, three hundred thirteen thousand, five hundred forty-seven".