661985167 has 8 divisors (see below), whose sum is σ = 680952096. Its totient is φ = 643074912.

The previous prime is 661985153. The next prime is 661985171. The reversal of 661985167 is 761589166.

It is a happy number.

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 661985167 - 2¹⁹ = 661460879 is a prime.

It is a super-2 number, since 2×661985167² = 876448722656035778, which contains 22 as substring.

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 661985167.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661985147) 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, 10113 + ... + 37765.

It is an arithmetic number, because the mean of its divisors is an integer number (85119012).

Almost surely, 2^661985167 is an apocalyptic number.

661985167 is a deficient number, since it is larger than the sum of its proper divisors (18966929).

661985167 is a wasteful number, since it uses less digits than its factorization.

661985167 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28337.

The product of its digits is 544320, while the sum is 49.

The square root of 661985167 is about 25729.0724084643. The cubic root of 661985167 is about 871.5308262048.

The spelling of 661985167 in words is "six hundred sixty-one million, nine hundred eighty-five thousand, one hundred sixty-seven".