1661155331 has 8 divisors (see below), whose sum is σ = 1823289024. Its totient is φ = 1500874920.

The previous prime is 1661155291. The next prime is 1661155337. The reversal of 1661155331 is 1335511661.

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 1661155331 - 2⁶ = 1661155267 is a prime.

It is a super-2 number, since 2×1661155331² = 5518874067419439122, which contains 22 as substring.

It is a Duffinian number.

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (1661155337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 461441 + ... + 465026.

It is an arithmetic number, because the mean of its divisors is an integer number (227911128).

Almost surely, 2^1661155331 is an apocalyptic number.

1661155331 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1661155331 is a deficient number, since it is larger than the sum of its proper divisors (162133693).

1661155331 is a wasteful number, since it uses less digits than its factorization.

1661155331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 926641.

The product of its digits is 8100, while the sum is 32.

The square root of 1661155331 is about 40757.2733509002. The cubic root of 1661155331 is about 1184.3227761157.

Adding to 1661155331 its reverse (1335511661), we get a palindrome (2996666992).

The spelling of 1661155331 in words is "one billion, six hundred sixty-one million, one hundred fifty-five thousand, three hundred thirty-one".