1361001661 has 4 divisors (see below), whose sum is σ = 1361189500. Its totient is φ = 1360813824.

The previous prime is 1361001659. The next prime is 1361001667. The reversal of 1361001661 is 1661001631.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1156340025 + 204661636 = 34005^2 + 14306^2 .

It is a cyclic number.

It is not a de Polignac number, because 1361001661 - 2¹ = 1361001659 is a prime.

It is a super-3 number, since 3×1361001661³ (a number of 28 digits) contains 333 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 (1361001667) 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, 82596 + ... + 97693.

It is an arithmetic number, because the mean of its divisors is an integer number (340297375).

Almost surely, 2^1361001661 is an apocalyptic number.

It is an amenable number.

1361001661 is a deficient number, since it is larger than the sum of its proper divisors (187839).

1361001661 is an equidigital number, since it uses as much as digits as its factorization.

1361001661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187838.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 1361001661 is about 36891.7560032048. The cubic root of 1361001661 is about 1108.2035875231.

The spelling of 1361001661 in words is "one billion, three hundred sixty-one million, one thousand, six hundred sixty-one".