661309441 has 4 divisors (see below), whose sum is σ = 712179412. Its totient is φ = 610439472.

The previous prime is 661309403. The next prime is 661309457. The reversal of 661309441 is 144903166.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 208513600 + 452795841 = 14440^2 + 21279^2 .

It is a cyclic number.

It is not a de Polignac number, because 661309441 - 2⁹ = 661308929 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661309397 and 661309406.

It is not an unprimeable number, because it can be changed into a prime (661309241) 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, 25434966 + ... + 25434991.

It is an arithmetic number, because the mean of its divisors is an integer number (178044853).

Almost surely, 2^661309441 is an apocalyptic number.

It is an amenable number.

661309441 is a deficient number, since it is larger than the sum of its proper divisors (50869971).

661309441 is a wasteful number, since it uses less digits than its factorization.

661309441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50869970.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 661309441 is about 25715.9374902025. The cubic root of 661309441 is about 871.2341848488.

The spelling of 661309441 in words is "six hundred sixty-one million, three hundred nine thousand, four hundred forty-one".