661017847 has 32 divisors (see below), whose sum is σ = 815160320. Its totient is φ = 523480320.

The previous prime is 661017829. The next prime is 661017853. The reversal of 661017847 is 748710166.

It is a cyclic number.

It is not a de Polignac number, because 661017847 - 2¹¹ = 661015799 is a prime.

It is a Duffinian number.

661017847 is a modest number, since divided by 17847 gives 661 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661017857) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 999697 + ... + 1000357.

It is an arithmetic number, because the mean of its divisors is an integer number (25473760).

Almost surely, 2^661017847 is an apocalyptic number.

661017847 is a deficient number, since it is larger than the sum of its proper divisors (154142473).

661017847 is a wasteful number, since it uses less digits than its factorization.

661017847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 863.

The product of its (nonzero) digits is 56448, while the sum is 40.

The square root of 661017847 is about 25710.2673459457. The cubic root of 661017847 is about 871.1061136849.

The spelling of 661017847 in words is "six hundred sixty-one million, seventeen thousand, eight hundred forty-seven".