691094989 has 8 divisors (see below), whose sum is σ = 751085720. Its totient is φ = 632079936.

The previous prime is 691094981. The next prime is 691095001. The reversal of 691094989 is 989490196.

It can be written as a sum of positive squares in 4 ways, for example, as 175032900 + 516062089 = 13230^2 + 22717^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 691094989 - 2³ = 691094981 is a prime.

It is a super-2 number, since 2×691094989² = 955224567641820242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691094981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 242442 + ... + 245275.

It is an arithmetic number, because the mean of its divisors is an integer number (93885715).

Almost surely, 2^691094989 is an apocalyptic number.

It is an amenable number.

691094989 is a deficient number, since it is larger than the sum of its proper divisors (59990731).

691094989 is a wasteful number, since it uses less digits than its factorization.

691094989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487839.

The product of its (nonzero) digits is 1259712, while the sum is 55.

The square root of 691094989 is about 26288.6855700318. The cubic root of 691094989 is about 884.1227814995.

The spelling of 691094989 in words is "six hundred ninety-one million, ninety-four thousand, nine hundred eighty-nine".