780978989 has 4 divisors (see below), whose sum is σ = 892547424. Its totient is φ = 669410556.

The previous prime is 780978967. The next prime is 780979027. The reversal of 780978989 is 989879087.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 989879087 = 4241 ⋅233407.

It is a cyclic number.

It is not a de Polignac number, because 780978989 - 2¹² = 780974893 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (780978959) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55784207 + ... + 55784220.

It is an arithmetic number, because the mean of its divisors is an integer number (223136856).

Almost surely, 2^780978989 is an apocalyptic number.

It is an amenable number.

780978989 is a deficient number, since it is larger than the sum of its proper divisors (111568435).

780978989 is a wasteful number, since it uses less digits than its factorization.

780978989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111568434.

The product of its (nonzero) digits is 18289152, while the sum is 65.

The square root of 780978989 is about 27946.0013060903. The cubic root of 780978989 is about 920.9013649502.

The spelling of 780978989 in words is "seven hundred eighty million, nine hundred seventy-eight thousand, nine hundred eighty-nine".