21455503613497 has 2 divisors, whose sum is σ = 21455503613498. Its totient is φ = 21455503613496.

The previous prime is 21455503613431. The next prime is 21455503613507. The reversal of 21455503613497 is 79431630555412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17724950430201 + 3730553183296 = 4210101^2 + 1931464^2 .

It is a cyclic number.

It is not a de Polignac number, because 21455503613497 - 2¹¹ = 21455503611449 is a prime.

It is not a weakly prime, because it can be changed into another prime (21455503613897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727751806748 + 10727751806749.

It is an arithmetic number, because the mean of its divisors is an integer number (10727751806749).

Almost surely, 2^{21455503613497} is an apocalyptic number.

It is an amenable number.

21455503613497 is a deficient number, since it is larger than the sum of its proper divisors (1).

21455503613497 is an equidigital number, since it uses as much as digits as its factorization.

21455503613497 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13608000, while the sum is 55.

The spelling of 21455503613497 in words is "twenty-one trillion, four hundred fifty-five billion, five hundred three million, six hundred thirteen thousand, four hundred ninety-seven".