1661824939 has 2 divisors, whose sum is σ = 1661824940. Its totient is φ = 1661824938.

The previous prime is 1661824937. The next prime is 1661824951. The reversal of 1661824939 is 9394281661.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1661824939 - 2¹ = 1661824937 is a prime.

Together with 1661824937, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 1661824892 and 1661824901.

It is not a weakly prime, because it can be changed into another prime (1661824937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830912469 + 830912470.

It is an arithmetic number, because the mean of its divisors is an integer number (830912470).

Almost surely, 2^1661824939 is an apocalyptic number.

1661824939 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661824939 is an equidigital number, since it uses as much as digits as its factorization.

1661824939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 49.

The square root of 1661824939 is about 40765.4871061294. The cubic root of 1661824939 is about 1184.4818873595.

The spelling of 1661824939 in words is "one billion, six hundred sixty-one million, eight hundred twenty-four thousand, nine hundred thirty-nine".