661044462511551 has 32 divisors (see below), whose sum is σ = 896086051015680. Its totient is φ = 433400835542400.

The previous prime is 661044462511529. The next prime is 661044462511553. The reversal of 661044462511551 is 155115264440166.

It is a happy number.

It is not a de Polignac number, because 661044462511551 - 2⁵ = 661044462511519 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661044462511494 and 661044462511503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661044462511553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 74926266 + ... + 83282856.

It is an arithmetic number, because the mean of its divisors is an integer number (28002689094240).

Almost surely, 2^{661044462511551} is an apocalyptic number.

661044462511551 is a deficient number, since it is larger than the sum of its proper divisors (235041588504129).

661044462511551 is a wasteful number, since it uses less digits than its factorization.

661044462511551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8358127.

The product of its (nonzero) digits is 3456000, while the sum is 51.

The spelling of 661044462511551 in words is "six hundred sixty-one trillion, forty-four billion, four hundred sixty-two million, five hundred eleven thousand, five hundred fifty-one".