1661634274 has 4 divisors (see below), whose sum is σ = 2492451414. Its totient is φ = 830817136.

The previous prime is 1661634223. The next prime is 1661634313. The reversal of 1661634274 is 4724361661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 4724361661 = 1051 ⋅4495111.

It can be written as a sum of positive squares in only one way, i.e., 1600560049 + 61074225 = 40007^2 + 7815^2 .

It is a super-2 number, since 2×1661634274² = 5522056921063014152, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 415408567 + ... + 415408570.

Almost surely, 2^1661634274 is an apocalyptic number.

1661634274 is a deficient number, since it is larger than the sum of its proper divisors (830817140).

1661634274 is an equidigital number, since it uses as much as digits as its factorization.

1661634274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830817139.

The product of its digits is 145152, while the sum is 40.

The square root of 1661634274 is about 40763.1484799690. The cubic root of 1661634274 is about 1184.4365861826.

The spelling of 1661634274 in words is "one billion, six hundred sixty-one million, six hundred thirty-four thousand, two hundred seventy-four".