1661504724001 has 4 divisors (see below), whose sum is σ = 1662775960752. Its totient is φ = 1660233487252.

The previous prime is 1661504723987. The next prime is 1661504724037. The reversal of 1661504724001 is 1004274051661.

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 1661504724001 - 2¹⁵ = 1661504691233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661504724041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 635616415 + ... + 635619028.

It is an arithmetic number, because the mean of its divisors is an integer number (415693990188).

Almost surely, 2^{1661504724001} is an apocalyptic number.

It is an amenable number.

1661504724001 is a deficient number, since it is larger than the sum of its proper divisors (1271236751).

1661504724001 is a wasteful number, since it uses less digits than its factorization.

1661504724001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1271236750.

The product of its (nonzero) digits is 40320, while the sum is 37.

Adding to 1661504724001 its reverse (1004274051661), we get a palindrome (2665778775662).

The spelling of 1661504724001 in words is "one trillion, six hundred sixty-one billion, five hundred four million, seven hundred twenty-four thousand, one".