897779991 has 16 divisors (see below), whose sum is σ = 1203686624. Its totient is φ = 595206144.

The previous prime is 897779957. The next prime is 897780007. The reversal of 897779991 is 199977798.

It is a happy number.

It is not a de Polignac number, because 897779991 - 2⁹ = 897779479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (897779291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 778071 + ... + 779223.

It is an arithmetic number, because the mean of its divisors is an integer number (75230414).

Almost surely, 2^897779991 is an apocalyptic number.

897779991 is a deficient number, since it is larger than the sum of its proper divisors (305906633).

897779991 is a wasteful number, since it uses less digits than its factorization.

897779991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2370.

The product of its digits is 18003384, while the sum is 66.

The square root of 897779991 is about 29962.9770049640. The cubic root of 897779991 is about 964.6948809402.

The spelling of 897779991 in words is "eight hundred ninety-seven million, seven hundred seventy-nine thousand, nine hundred ninety-one".