1567661 has 2 divisors, whose sum is σ = 1567662. Its totient is φ = 1567660.

The previous prime is 1567637. The next prime is 1567667. The reversal of 1567661 is 1667651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1525225 + 42436 = 1235^2 + 206^2 .

It is an emirp because it is prime and its reverse (1667651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1567661 - 2¹⁰ = 1566637 is a prime.

It is a super-2 number, since 2×1567661² = 4915122021842, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1567667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 783830 + 783831.

It is an arithmetic number, because the mean of its divisors is an integer number (783831).

2^1567661 is an apocalyptic number.

It is an amenable number.

1567661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1567661 is an equidigital number, since it uses as much as digits as its factorization.

1567661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7560, while the sum is 32.

The square root of 1567661 is about 1252.0626981106. The cubic root of 1567661 is about 116.1673417108.

It can be divided in two parts, 15 and 67661, that added together give a palindrome (67676).

The spelling of 1567661 in words is "one million, five hundred sixty-seven thousand, six hundred sixty-one".