21550120399 has 2 divisors, whose sum is σ = 21550120400. Its totient is φ = 21550120398.

The previous prime is 21550120387. The next prime is 21550120483. The reversal of 21550120399 is 99302105512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21550120399 - 2¹¹ = 21550118351 is a prime.

It is a super-2 number, since 2×21550120399² (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 (21550120309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10775060199 + 10775060200.

It is an arithmetic number, because the mean of its divisors is an integer number (10775060200).

Almost surely, 2^21550120399 is an apocalyptic number.

21550120399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21550120399 is an equidigital number, since it uses as much as digits as its factorization.

21550120399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24300, while the sum is 37.

The spelling of 21550120399 in words is "twenty-one billion, five hundred fifty million, one hundred twenty thousand, three hundred ninety-nine".