1661431 has 2 divisors, whose sum is σ = 1661432. Its totient is φ = 1661430.

The previous prime is 1661353. The next prime is 1661437. The reversal of 1661431 is 1341661.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661431 is a prime.

It is a super-2 number, since 2×1661431² = 5520705935522, 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 (1661437) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830715 + 830716.

It is an arithmetic number, because the mean of its divisors is an integer number (830716).

2^1661431 is an apocalyptic number.

1661431 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661431 is an equidigital number, since it uses as much as digits as its factorization.

1661431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 22.

The square root of 1661431 is about 1288.9650887437. The cubic root of 1661431 is about 118.4388285345.

The spelling of 1661431 in words is "one million, six hundred sixty-one thousand, four hundred thirty-one".