661433641 has 4 divisors (see below), whose sum is σ = 721563984. Its totient is φ = 601303300.

The previous prime is 661433627. The next prime is 661433677. The reversal of 661433641 is 146334166.

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 661433641 - 2²³ = 653045033 is a prime.

It is a super-2 number, since 2×661433641² = 874988922893033762, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661433597 and 661433606.

It is not an unprimeable number, because it can be changed into a prime (661433041) 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, 30065155 + ... + 30065176.

It is an arithmetic number, because the mean of its divisors is an integer number (180390996).

Almost surely, 2^661433641 is an apocalyptic number.

It is an amenable number.

661433641 is a deficient number, since it is larger than the sum of its proper divisors (60130343).

661433641 is a wasteful number, since it uses less digits than its factorization.

661433641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60130342.

The product of its digits is 31104, while the sum is 34.

The square root of 661433641 is about 25718.3522217113. The cubic root of 661433641 is about 871.2887233677.

The spelling of 661433641 in words is "six hundred sixty-one million, four hundred thirty-three thousand, six hundred forty-one".