1662611721 has 8 divisors (see below), whose sum is σ = 2217198144. Its totient is φ = 1108216560.

The previous prime is 1662611711. The next prime is 1662611729. The reversal of 1662611721 is 1271162661.

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

It is not a de Polignac number, because 1662611721 - 2⁷ = 1662611593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1662611729) 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, 26125 + ... + 63306.

It is an arithmetic number, because the mean of its divisors is an integer number (277149768).

Almost surely, 2^1662611721 is an apocalyptic number.

It is an amenable number.

1662611721 is a deficient number, since it is larger than the sum of its proper divisors (554586423).

1662611721 is an equidigital number, since it uses as much as digits as its factorization.

1662611721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95631.

The product of its digits is 6048, while the sum is 33.

The square root of 1662611721 is about 40775.1360635375. The cubic root of 1662611721 is about 1184.6687867079.

The spelling of 1662611721 in words is "one billion, six hundred sixty-two million, six hundred eleven thousand, seven hundred twenty-one".