1661572667 has 16 divisors (see below), whose sum is σ = 1761246720. Its totient is φ = 1563170400.

The previous prime is 1661572657. The next prime is 1661572669. The reversal of 1661572667 is 7662751661.

It is a cyclic number.

It is not a de Polignac number, because 1661572667 - 2⁴ = 1661572651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661572669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2710253 + ... + 2710865.

It is an arithmetic number, because the mean of its divisors is an integer number (110077920).

Almost surely, 2^1661572667 is an apocalyptic number.

1661572667 is a deficient number, since it is larger than the sum of its proper divisors (99674053).

1661572667 is a wasteful number, since it uses less digits than its factorization.

1661572667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1394.

The product of its digits is 635040, while the sum is 47.

The square root of 1661572667 is about 40762.3928026803. The cubic root of 1661572667 is about 1184.4219478859.

The spelling of 1661572667 in words is "one billion, six hundred sixty-one million, five hundred seventy-two thousand, six hundred sixty-seven".