1661887637039 has 4 divisors (see below), whose sum is σ = 1899300156624. Its totient is φ = 1424475117456.

The previous prime is 1661887637029. The next prime is 1661887637077. The reversal of 1661887637039 is 9307367881661.

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 1661887637039 - 2¹⁶ = 1661887571503 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 (1661887637029) 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, 118706259782 + ... + 118706259795.

It is an arithmetic number, because the mean of its divisors is an integer number (474825039156).

Almost surely, 2^{1661887637039} is an apocalyptic number.

1661887637039 is a deficient number, since it is larger than the sum of its proper divisors (237412519585).

1661887637039 is an equidigital number, since it uses as much as digits as its factorization.

1661887637039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237412519584.

The product of its (nonzero) digits is 54867456, while the sum is 65.

The spelling of 1661887637039 in words is "one trillion, six hundred sixty-one billion, eight hundred eighty-seven million, six hundred thirty-seven thousand, thirty-nine".