661756047 has 8 divisors (see below), whose sum is σ = 885527856. Its totient is φ = 439577472.

The previous prime is 661756027. The next prime is 661756057. The reversal of 661756047 is 740657166.

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

It is not a de Polignac number, because 661756047 - 2¹⁶ = 661690511 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661756027) 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, 397338 + ... + 398999.

It is an arithmetic number, because the mean of its divisors is an integer number (110690982).

Almost surely, 2^661756047 is an apocalyptic number.

661756047 is a deficient number, since it is larger than the sum of its proper divisors (223771809).

661756047 is a wasteful number, since it uses less digits than its factorization.

661756047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 796617.

The product of its (nonzero) digits is 211680, while the sum is 42.

The square root of 661756047 is about 25724.6194724043. The cubic root of 661756047 is about 871.4302659531.

The spelling of 661756047 in words is "six hundred sixty-one million, seven hundred fifty-six thousand, forty-seven".