1661501782023 has 4 divisors (see below), whose sum is σ = 2215335709368. Its totient is φ = 1107667854680.

The previous prime is 1661501782021. The next prime is 1661501782063. The reversal of 1661501782023 is 3202871051661.

It is a happy number.

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 1661501782023 - 2¹ = 1661501782021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661501782021) 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, 276916963668 + ... + 276916963673.

It is an arithmetic number, because the mean of its divisors is an integer number (553833927342).

Almost surely, 2^{1661501782023} is an apocalyptic number.

1661501782023 is a deficient number, since it is larger than the sum of its proper divisors (553833927345).

1661501782023 is an equidigital number, since it uses as much as digits as its factorization.

1661501782023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553833927344.

The product of its (nonzero) digits is 120960, while the sum is 42.

The spelling of 1661501782023 in words is "one trillion, six hundred sixty-one billion, five hundred one million, seven hundred eighty-two thousand, twenty-three".