545640661 has 4 divisors (see below), whose sum is σ = 569364192. Its totient is φ = 521917132.

The previous prime is 545640647. The next prime is 545640677. The reversal of 545640661 is 166046545.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-545640661 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 545640661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (545640611) 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, 11861731 + ... + 11861776.

It is an arithmetic number, because the mean of its divisors is an integer number (142341048).

Almost surely, 2^545640661 is an apocalyptic number.

It is an amenable number.

545640661 is a deficient number, since it is larger than the sum of its proper divisors (23723531).

545640661 is a wasteful number, since it uses less digits than its factorization.

545640661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23723530.

The product of its (nonzero) digits is 86400, while the sum is 37.

The square root of 545640661 is about 23358.9524807942. The cubic root of 545640661 is about 817.1508600216.

The spelling of 545640661 in words is "five hundred forty-five million, six hundred forty thousand, six hundred sixty-one".