1661528723 has 6 divisors (see below), whose sum is σ = 1685265252. Its totient is φ = 1638121940.

The previous prime is 1661528719. The next prime is 1661528749. The reversal of 1661528723 is 3278251661.

It is not a de Polignac number, because 1661528723 - 2² = 1661528719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661528753) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 159761 + ... + 169842.

It is an arithmetic number, because the mean of its divisors is an integer number (280877542).

Almost surely, 2^1661528723 is an apocalyptic number.

1661528723 is a deficient number, since it is larger than the sum of its proper divisors (23736529).

1661528723 is an frugal number, since it uses more digits than its factorization.

1661528723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329745 (or 329674 counting only the distinct ones).

The product of its digits is 120960, while the sum is 41.

The square root of 1661528723 is about 40761.8537728597. The cubic root of 1661528723 is about 1184.4115062327.

The spelling of 1661528723 in words is "one billion, six hundred sixty-one million, five hundred twenty-eight thousand, seven hundred twenty-three".