1205461661 has 4 divisors (see below), whose sum is σ = 1205531424. Its totient is φ = 1205391900.

The previous prime is 1205461639. The next prime is 1205461693. The reversal of 1205461661 is 1661645021.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1661645021 = 71 ⋅23403451.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1205461661 is a prime.

It is a super-2 number, since 2×1205461661² = 2906275632281757842, 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 (1205461861) 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, 12416 + ... + 50646.

It is an arithmetic number, because the mean of its divisors is an integer number (301382856).

Almost surely, 2^1205461661 is an apocalyptic number.

It is an amenable number.

1205461661 is a deficient number, since it is larger than the sum of its proper divisors (69763).

1205461661 is an equidigital number, since it uses as much as digits as its factorization.

1205461661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69762.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 1205461661 is about 34719.7589421355. The cubic root of 1205461661 is about 1064.2683185799.

The spelling of 1205461661 in words is "one billion, two hundred five million, four hundred sixty-one thousand, six hundred sixty-one".