1661474278 has 16 divisors (see below), whose sum is σ = 2504884176. Its totient is φ = 826524160.

The previous prime is 1661474273. The next prime is 1661474281. The reversal of 1661474278 is 8724741661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661474273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 344250 + ... + 349042.

It is an arithmetic number, because the mean of its divisors is an integer number (156555261).

Almost surely, 2^1661474278 is an apocalyptic number.

1661474278 is a deficient number, since it is larger than the sum of its proper divisors (843409898).

1661474278 is a wasteful number, since it uses less digits than its factorization.

1661474278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5639.

The product of its digits is 451584, while the sum is 46.

The square root of 1661474278 is about 40761.1859248477. The cubic root of 1661474278 is about 1184.3985691529.

The spelling of 1661474278 in words is "one billion, six hundred sixty-one million, four hundred seventy-four thousand, two hundred seventy-eight".