661861802 has 32 divisors (see below), whose sum is σ = 1163054592. Its totient is φ = 276591744.

The previous prime is 661861747. The next prime is 661861807. The reversal of 661861802 is 208168166.

It is a super-2 number, since 2×661861802² = 876122089893374408, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661861807) by changing a digit.

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, 191078 + ... + 194510.

It is an arithmetic number, because the mean of its divisors is an integer number (36345456).

Almost surely, 2^661861802 is an apocalyptic number.

661861802 is a deficient number, since it is larger than the sum of its proper divisors (501192790).

661861802 is a wasteful number, since it uses less digits than its factorization.

661861802 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3782.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 661861802 is about 25726.6749114611. The cubic root of 661861802 is about 871.4766844681.

The spelling of 661861802 in words is "six hundred sixty-one million, eight hundred sixty-one thousand, eight hundred two".