1661244769637 has 4 divisors (see below), whose sum is σ = 1661249415840. Its totient is φ = 1661240123436.

The previous prime is 1661244769631. The next prime is 1661244769711. The reversal of 1661244769637 is 7369674421661.

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 1661244769637 - 2²⁶ = 1661177660773 is a prime.

It is a super-2 number, since 2×1661244769637² (a number of 25 digits) contains 22 as substring.

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 1661244769637.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661244769631) 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, 1737587 + ... + 2518272.

It is an arithmetic number, because the mean of its divisors is an integer number (415312353960).

Almost surely, 2^{1661244769637} is an apocalyptic number.

It is an amenable number.

1661244769637 is a deficient number, since it is larger than the sum of its proper divisors (4646203).

1661244769637 is an equidigital number, since it uses as much as digits as its factorization.

1661244769637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4646202.

The product of its digits is 54867456, while the sum is 62.

The spelling of 1661244769637 in words is "one trillion, six hundred sixty-one billion, two hundred forty-four million, seven hundred sixty-nine thousand, six hundred thirty-seven".