21550500373 has 2 divisors, whose sum is σ = 21550500374. Its totient is φ = 21550500372.

The previous prime is 21550500287. The next prime is 21550500479. The reversal of 21550500373 is 37300505512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21205766884 + 344733489 = 145622^2 + 18567^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21550500373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21550507373) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10775250186 + 10775250187.

It is an arithmetic number, because the mean of its divisors is an integer number (10775250187).

Almost surely, 2^21550500373 is an apocalyptic number.

It is an amenable number.

21550500373 is a deficient number, since it is larger than the sum of its proper divisors (1).

21550500373 is an equidigital number, since it uses as much as digits as its factorization.

21550500373 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15750, while the sum is 31.

The spelling of 21550500373 in words is "twenty-one billion, five hundred fifty million, five hundred thousand, three hundred seventy-three".