21510369533 has 2 divisors, whose sum is σ = 21510369534. Its totient is φ = 21510369532.

The previous prime is 21510369481. The next prime is 21510369541. The reversal of 21510369533 is 33596301512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21426518884 + 83850649 = 146378^2 + 9157^2 .

It is a cyclic number.

It is not a de Polignac number, because 21510369533 - 2⁸ = 21510369277 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21510369563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755184766 + 10755184767.

It is an arithmetic number, because the mean of its divisors is an integer number (10755184767).

Almost surely, 2^21510369533 is an apocalyptic number.

It is an amenable number.

21510369533 is a deficient number, since it is larger than the sum of its proper divisors (1).

21510369533 is an equidigital number, since it uses as much as digits as its factorization.

21510369533 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72900, while the sum is 38.

The spelling of 21510369533 in words is "twenty-one billion, five hundred ten million, three hundred sixty-nine thousand, five hundred thirty-three".