2661543917 has 4 divisors (see below), whose sum is σ = 2666410176. Its totient is φ = 2656677660.

The previous prime is 2661543889. The next prime is 2661543943. The reversal of 2661543917 is 7193451662.

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 not a de Polignac number, because 2661543917 - 2¹² = 2661539821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661543947) 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, 2432309 + ... + 2433402.

It is an arithmetic number, because the mean of its divisors is an integer number (666602544).

Almost surely, 2^2661543917 is an apocalyptic number.

It is an amenable number.

2661543917 is a deficient number, since it is larger than the sum of its proper divisors (4866259).

2661543917 is an equidigital number, since it uses as much as digits as its factorization.

2661543917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4866258.

The product of its digits is 272160, while the sum is 44.

The square root of 2661543917 is about 51590.1532949845. The cubic root of 2661543917 is about 1385.8340004226.

The spelling of 2661543917 in words is "two billion, six hundred sixty-one million, five hundred forty-three thousand, nine hundred seventeen".