661450643 has 8 divisors (see below), whose sum is σ = 756475488. Its totient is φ = 566558784.

The previous prime is 661450631. The next prime is 661450753. The reversal of 661450643 is 346054166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661450643 - 2¹⁰ = 661449619 is a prime.

It is a super-2 number, since 2×661450643² = 875033906250226898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661450613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22346 + ... + 42687.

It is an arithmetic number, because the mean of its divisors is an integer number (94559436).

Almost surely, 2^661450643 is an apocalyptic number.

661450643 is a deficient number, since it is larger than the sum of its proper divisors (95024845).

661450643 is a wasteful number, since it uses less digits than its factorization.

661450643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66493.

The product of its (nonzero) digits is 51840, while the sum is 35.

The square root of 661450643 is about 25718.6827617590. The cubic root of 661450643 is about 871.2961887293.

The spelling of 661450643 in words is "six hundred sixty-one million, four hundred fifty thousand, six hundred forty-three".