890978509 has 2 divisors, whose sum is σ = 890978510. Its totient is φ = 890978508.

The previous prime is 890978507. The next prime is 890978549. The reversal of 890978509 is 905879098.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 757460484 + 133518025 = 27522^2 + 11555^2 .

It is a cyclic number.

It is not a de Polignac number, because 890978509 - 2¹ = 890978507 is a prime.

Together with 890978507, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 890978509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (890978507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445489254 + 445489255.

It is an arithmetic number, because the mean of its divisors is an integer number (445489255).

Almost surely, 2^890978509 is an apocalyptic number.

It is an amenable number.

890978509 is a deficient number, since it is larger than the sum of its proper divisors (1).

890978509 is an equidigital number, since it uses as much as digits as its factorization.

890978509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1632960, while the sum is 55.

The square root of 890978509 is about 29849.2631232330. The cubic root of 890978509 is about 962.2525623349.

The spelling of 890978509 in words is "eight hundred ninety million, nine hundred seventy-eight thousand, five hundred nine".