1661626645 has 8 divisors (see below), whose sum is σ = 2278802304. Its totient is φ = 1139401104.

The previous prime is 1661626643. The next prime is 1661626667. The reversal of 1661626645 is 5466261661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1661626645 - 2¹ = 1661626643 is a prime.

It is a super-2 number, since 2×1661626645² = 5522006214747912050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661626643) 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, 23737489 + ... + 23737558.

It is an arithmetic number, because the mean of its divisors is an integer number (284850288).

Almost surely, 2^1661626645 is an apocalyptic number.

It is an amenable number.

1661626645 is a deficient number, since it is larger than the sum of its proper divisors (617175659).

1661626645 is an equidigital number, since it uses as much as digits as its factorization.

1661626645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47475059.

The product of its digits is 311040, while the sum is 43.

The square root of 1661626645 is about 40763.0549026934. The cubic root of 1661626645 is about 1184.4347734932.

The spelling of 1661626645 in words is "one billion, six hundred sixty-one million, six hundred twenty-six thousand, six hundred forty-five".