661851355 has 16 divisors (see below), whose sum is σ = 867658464. Its totient is φ = 480660480.

The previous prime is 661851343. The next prime is 661851367. The reversal of 661851355 is 553158166.

It is an interprime number because it is at equal distance from previous prime (661851343) and next prime (661851367).

It is not a de Polignac number, because 661851355 - 2¹⁵ = 661818587 is a prime.

It is a super-2 number, since 2×661851355² = 876094432230672050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32107 + ... + 48523.

It is an arithmetic number, because the mean of its divisors is an integer number (54228654).

Almost surely, 2^661851355 is an apocalyptic number.

661851355 is a deficient number, since it is larger than the sum of its proper divisors (205807109).

661851355 is a wasteful number, since it uses less digits than its factorization.

661851355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17166.

The product of its digits is 108000, while the sum is 40.

The square root of 661851355 is about 25726.4718723730. The cubic root of 661851355 is about 871.4720992386.

The spelling of 661851355 in words is "six hundred sixty-one million, eight hundred fifty-one thousand, three hundred fifty-five".