201655561997 has 2 divisors, whose sum is σ = 201655561998. Its totient is φ = 201655561996.

The previous prime is 201655561963. The next prime is 201655562041. The reversal of 201655561997 is 799165556102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 157328049316 + 44327512681 = 396646^2 + 210541^2 .

It is a cyclic number.

It is not a de Polignac number, because 201655561997 - 2²⁶ = 201588453133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201655561907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100827780998 + 100827780999.

It is an arithmetic number, because the mean of its divisors is an integer number (100827780999).

Almost surely, 2^201655561997 is an apocalyptic number.

It is an amenable number.

201655561997 is a deficient number, since it is larger than the sum of its proper divisors (1).

201655561997 is an equidigital number, since it uses as much as digits as its factorization.

201655561997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5103000, while the sum is 56.

The spelling of 201655561997 in words is "two hundred one billion, six hundred fifty-five million, five hundred sixty-one thousand, nine hundred ninety-seven".