21510019247 has 2 divisors, whose sum is σ = 21510019248. Its totient is φ = 21510019246.

The previous prime is 21510019243. The next prime is 21510019253. The reversal of 21510019247 is 74291001512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21510019247 - 2² = 21510019243 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21510019241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755009623 + 10755009624.

It is an arithmetic number, because the mean of its divisors is an integer number (10755009624).

Almost surely, 2^21510019247 is an apocalyptic number.

21510019247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21510019247 is an equidigital number, since it uses as much as digits as its factorization.

21510019247 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 32.

The spelling of 21510019247 in words is "twenty-one billion, five hundred ten million, nineteen thousand, two hundred forty-seven".