165603645551 has 4 divisors (see below), whose sum is σ = 166907611392. Its totient is φ = 164299679712.

The previous prime is 165603645541. The next prime is 165603645583. The reversal of 165603645551 is 155546306561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 165603645551 - 2¹⁰ = 165603644527 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 165603645496 and 165603645505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165603645541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 651982730 + ... + 651982983.

It is an arithmetic number, because the mean of its divisors is an integer number (41726902848).

Almost surely, 2^165603645551 is an apocalyptic number.

165603645551 is a deficient number, since it is larger than the sum of its proper divisors (1303965841).

165603645551 is a wasteful number, since it uses less digits than its factorization.

165603645551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1303965840.

The product of its (nonzero) digits is 1620000, while the sum is 47.

The spelling of 165603645551 in words is "one hundred sixty-five billion, six hundred three million, six hundred forty-five thousand, five hundred fifty-one".