661536743 has 8 divisors (see below), whose sum is σ = 756630912. Its totient is φ = 566589816.

The previous prime is 661536721. The next prime is 661536751. The reversal of 661536743 is 347635166.

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 661536743 - 2²⁶ = 594427879 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 661536743.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661538743) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27005 + ... + 45302.

It is an arithmetic number, because the mean of its divisors is an integer number (94578864).

Almost surely, 2^661536743 is an apocalyptic number.

661536743 is a deficient number, since it is larger than the sum of its proper divisors (95094169).

661536743 is a wasteful number, since it uses less digits than its factorization.

661536743 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73621.

The product of its digits is 272160, while the sum is 41.

The square root of 661536743 is about 25720.3565877303. The cubic root of 661536743 is about 871.3339921784. Note that the first 3 decimals are identical.

The spelling of 661536743 in words is "six hundred sixty-one million, five hundred thirty-six thousand, seven hundred forty-three".