1213661 has 2 divisors, whose sum is σ = 1213662. Its totient is φ = 1213660.

The previous prime is 1213657. The next prime is 1213673. The reversal of 1213661 is 1663121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 988036 + 225625 = 994^2 + 475^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213661 - 2² = 1213657 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606830 + 606831.

It is an arithmetic number, because the mean of its divisors is an integer number (606831).

2^1213661 is an apocalyptic number.

It is an amenable number.

1213661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213661 is an equidigital number, since it uses as much as digits as its factorization.

1213661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 216, while the sum is 20.

The square root of 1213661 is about 1101.6628340831. The cubic root of 1213661 is about 106.6675857126.

Adding to 1213661 its reverse (1663121), we get a palindrome (2876782).

The spelling of 1213661 in words is "one million, two hundred thirteen thousand, six hundred sixty-one".