21651404519 has 2 divisors, whose sum is σ = 21651404520. Its totient is φ = 21651404518.

The previous prime is 21651404503. The next prime is 21651404557. The reversal of 21651404519 is 91540415612.

It is an a-pointer prime, because the next prime (21651404557) can be obtained adding 21651404519 to its sum of digits (38).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21651404519 - 2⁴ = 21651404503 is a prime.

It is a super-2 number, since 2×21651404519² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21651604519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10825702259 + 10825702260.

It is an arithmetic number, because the mean of its divisors is an integer number (10825702260).

Almost surely, 2^21651404519 is an apocalyptic number.

21651404519 is a deficient number, since it is larger than the sum of its proper divisors (1).

21651404519 is an equidigital number, since it uses as much as digits as its factorization.

21651404519 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43200, while the sum is 38.

The spelling of 21651404519 in words is "twenty-one billion, six hundred fifty-one million, four hundred four thousand, five hundred nineteen".