661620142441 has 4 divisors (see below), whose sum is σ = 661951120000. Its totient is φ = 661289164884.

The previous prime is 661620142439. The next prime is 661620142529. The reversal of 661620142441 is 144241026166.

It is a happy number.

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 661620142441 - 2¹ = 661620142439 is a prime.

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 661620142441.

It is not an unprimeable number, because it can be changed into a prime (661620145441) 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, 165485781 + ... + 165489778.

It is an arithmetic number, because the mean of its divisors is an integer number (165487780000).

Almost surely, 2^661620142441 is an apocalyptic number.

It is an amenable number.

661620142441 is a deficient number, since it is larger than the sum of its proper divisors (330977559).

661620142441 is a wasteful number, since it uses less digits than its factorization.

661620142441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330977558.

The product of its (nonzero) digits is 55296, while the sum is 37.

The spelling of 661620142441 in words is "six hundred sixty-one billion, six hundred twenty million, one hundred forty-two thousand, four hundred forty-one".