20616620551 has 2 divisors, whose sum is σ = 20616620552. Its totient is φ = 20616620550.

The previous prime is 20616620543. The next prime is 20616620581. The reversal of 20616620551 is 15502661602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20616620551 - 2³ = 20616620543 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20616620581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10308310275 + 10308310276.

It is an arithmetic number, because the mean of its divisors is an integer number (10308310276).

Almost surely, 2^20616620551 is an apocalyptic number.

20616620551 is a deficient number, since it is larger than the sum of its proper divisors (1).

20616620551 is an equidigital number, since it uses as much as digits as its factorization.

20616620551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21600, while the sum is 34.

The spelling of 20616620551 in words is "twenty billion, six hundred sixteen million, six hundred twenty thousand, five hundred fifty-one".