21621555034319 has 2 divisors, whose sum is σ = 21621555034320. Its totient is φ = 21621555034318.

The previous prime is 21621555034291. The next prime is 21621555034441. The reversal of 21621555034319 is 91343055512612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21621555034319 - 2¹² = 21621555030223 is a prime.

It is a super-2 number, since 2×21621555034319² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21621558034319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810777517159 + 10810777517160.

It is an arithmetic number, because the mean of its divisors is an integer number (10810777517160).

Almost surely, 2^{21621555034319} is an apocalyptic number.

21621555034319 is a deficient number, since it is larger than the sum of its proper divisors (1).

21621555034319 is an equidigital number, since it uses as much as digits as its factorization.

21621555034319 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972000, while the sum is 47.

The spelling of 21621555034319 in words is "twenty-one trillion, six hundred twenty-one billion, five hundred fifty-five million, thirty-four thousand, three hundred nineteen".