21510271551547 has 2 divisors, whose sum is σ = 21510271551548. Its totient is φ = 21510271551546.

The previous prime is 21510271551499. The next prime is 21510271551557. The reversal of 21510271551547 is 74515517201512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21510271551547 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21510271551497 and 21510271551506.

It is not a weakly prime, because it can be changed into another prime (21510271551557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755135775773 + 10755135775774.

It is an arithmetic number, because the mean of its divisors is an integer number (10755135775774).

Almost surely, 2^{21510271551547} is an apocalyptic number.

21510271551547 is a deficient number, since it is larger than the sum of its proper divisors (1).

21510271551547 is an equidigital number, since it uses as much as digits as its factorization.

21510271551547 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 490000, while the sum is 46.

The spelling of 21510271551547 in words is "twenty-one trillion, five hundred ten billion, two hundred seventy-one million, five hundred fifty-one thousand, five hundred forty-seven".