661554366 has 32 divisors (see below), whose sum is σ = 1448568576. Its totient is φ = 199752000.

The previous prime is 661554349. The next prime is 661554367. The reversal of 661554366 is 663455166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661554367) 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, 711 + ... + 36381.

It is an arithmetic number, because the mean of its divisors is an integer number (45267768).

Almost surely, 2^661554366 is an apocalyptic number.

661554366 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

661554366 is an abundant number, since it is smaller than the sum of its proper divisors (787014210).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661554366 is a wasteful number, since it uses less digits than its factorization.

661554366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35968.

The product of its digits is 388800, while the sum is 42.

The square root of 661554366 is about 25720.6991740116. The cubic root of 661554366 is about 871.3417294068.

The spelling of 661554366 in words is "six hundred sixty-one million, five hundred fifty-four thousand, three hundred sixty-six".