21512671919 has 2 divisors, whose sum is σ = 21512671920. Its totient is φ = 21512671918.

The previous prime is 21512671907. The next prime is 21512671969. The reversal of 21512671919 is 91917621512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21512671919 is a prime.

It is a super-3 number, since 3×21512671919³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 21512671919.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21512671969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10756335959 + 10756335960.

It is an arithmetic number, because the mean of its divisors is an integer number (10756335960).

Almost surely, 2^21512671919 is an apocalyptic number.

21512671919 is a deficient number, since it is larger than the sum of its proper divisors (1).

21512671919 is an equidigital number, since it uses as much as digits as its factorization.

21512671919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 44.

The spelling of 21512671919 in words is "twenty-one billion, five hundred twelve million, six hundred seventy-one thousand, nine hundred nineteen".