1661156123 has 12 divisors (see below), whose sum is σ = 1870438584. Its totient is φ = 1473304800.

The previous prime is 1661156093. The next prime is 1661156131. The reversal of 1661156123 is 3216511661.

It is not a de Polignac number, because 1661156123 - 2⁶ = 1661156059 is a prime.

It is a super-2 number, since 2×1661156123² = 5518879329960782258, which contains 22 as substring.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1661156123.

It is not an unprimeable number, because it can be changed into a prime (1661156143) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 162461 + ... + 172382.

It is an arithmetic number, because the mean of its divisors is an integer number (155869882).

Almost surely, 2^1661156123 is an apocalyptic number.

1661156123 is a deficient number, since it is larger than the sum of its proper divisors (209282461).

1661156123 is a wasteful number, since it uses less digits than its factorization.

1661156123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334906 (or 334895 counting only the distinct ones).

The product of its digits is 6480, while the sum is 32.

The square root of 1661156123 is about 40757.2830669563. The cubic root of 1661156123 is about 1184.3229643348.

Adding to 1661156123 its reverse (3216511661), we get a palindrome (4877667784).

The spelling of 1661156123 in words is "one billion, six hundred sixty-one million, one hundred fifty-six thousand, one hundred twenty-three".