1661155061 has 4 divisors (see below), whose sum is σ = 1718436300. Its totient is φ = 1603873824.

The previous prime is 1661155049. The next prime is 1661155073. The reversal of 1661155061 is 1605511661.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1661155049) and next prime (1661155073).

It can be written as a sum of positive squares in 2 ways, for example, as 1396442161 + 264712900 = 37369^2 + 16270^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661155061 - 2¹⁸ = 1660892917 is a prime.

It is a super-2 number, since 2×1661155061² = 5518872273371827442, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661155021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28640576 + ... + 28640633.

It is an arithmetic number, because the mean of its divisors is an integer number (429609075).

Almost surely, 2^1661155061 is an apocalyptic number.

It is an amenable number.

1661155061 is a deficient number, since it is larger than the sum of its proper divisors (57281239).

1661155061 is an equidigital number, since it uses as much as digits as its factorization.

1661155061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57281238.

The product of its (nonzero) digits is 5400, while the sum is 32.

The square root of 1661155061 is about 40757.2700386078. The cubic root of 1661155061 is about 1184.3227119501.

The spelling of 1661155061 in words is "one billion, six hundred sixty-one million, one hundred fifty-five thousand, sixty-one".