21193620551 has 2 divisors, whose sum is σ = 21193620552. Its totient is φ = 21193620550.

The previous prime is 21193620533. The next prime is 21193620557. The reversal of 21193620551 is 15502639112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21193620551 - 2¹⁰ = 21193619527 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21193620557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10596810275 + 10596810276.

It is an arithmetic number, because the mean of its divisors is an integer number (10596810276).

Almost surely, 2^21193620551 is an apocalyptic number.

21193620551 is a deficient number, since it is larger than the sum of its proper divisors (1).

21193620551 is an equidigital number, since it uses as much as digits as its factorization.

21193620551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16200, while the sum is 35.

The spelling of 21193620551 in words is "twenty-one billion, one hundred ninety-three million, six hundred twenty thousand, five hundred fifty-one".