1651660661 has 8 divisors (see below), whose sum is σ = 1891460544. Its totient is φ = 1412822880.

The previous prime is 1651660651. The next prime is 1651660669. The reversal of 1651660661 is 1660661561.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-1651660661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1651660669) 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 7 ways as a sum of consecutive naturals, for example, 236840 + ... + 243713.

It is an arithmetic number, because the mean of its divisors is an integer number (236432568).

Almost surely, 2^1651660661 is an apocalyptic number.

It is an amenable number.

1651660661 is a deficient number, since it is larger than the sum of its proper divisors (239799883).

1651660661 is an equidigital number, since it uses as much as digits as its factorization.

1651660661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 481051.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 1651660661 is about 40640.6282062667. The cubic root of 1651660661 is about 1182.0620511247.

It can be divided in two parts, 16516 and 60661, that added together give a palindrome (77177).

The spelling of 1651660661 in words is "one billion, six hundred fifty-one million, six hundred sixty thousand, six hundred sixty-one".