26691989 has 4 divisors (see below), whose sum is σ = 28262124. Its totient is φ = 25121856.

The previous prime is 26691947. The next prime is 26691991. The reversal of 26691989 is 98919662.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21996100 + 4695889 = 4690^2 + 2167^2 .

It is a cyclic number.

It is not a de Polignac number, because 26691989 - 2⁸ = 26691733 is a prime.

It is a super-2 number, since 2×26691989² = 1424924553552242, 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 (26661989) 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 3 ways as a sum of consecutive naturals, for example, 785042 + ... + 785075.

It is an arithmetic number, because the mean of its divisors is an integer number (7065531).

Almost surely, 2^26691989 is an apocalyptic number.

It is an amenable number.

26691989 is a deficient number, since it is larger than the sum of its proper divisors (1570135).

26691989 is a wasteful number, since it uses less digits than its factorization.

26691989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1570134.

The product of its digits is 419904, while the sum is 50.

The square root of 26691989 is about 5166.4290375461. The cubic root of 26691989 is about 298.8548528739.

The spelling of 26691989 in words is "twenty-six million, six hundred ninety-one thousand, nine hundred eighty-nine".