661006747 has 4 divisors (see below), whose sum is σ = 661350640. Its totient is φ = 660662856.

The previous prime is 661006711. The next prime is 661006777. The reversal of 661006747 is 747600166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 747600166 = 2 ⋅373800083.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661006747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661006777) 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, 169047 + ... + 172912.

It is an arithmetic number, because the mean of its divisors is an integer number (165337660).

Almost surely, 2^661006747 is an apocalyptic number.

661006747 is a deficient number, since it is larger than the sum of its proper divisors (343893).

661006747 is a wasteful number, since it uses less digits than its factorization.

661006747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343892.

The product of its (nonzero) digits is 42336, while the sum is 37.

The square root of 661006747 is about 25710.0514779726. The cubic root of 661006747 is about 871.1012377036.

The spelling of 661006747 in words is "six hundred sixty-one million, six thousand, seven hundred forty-seven".