26691990 has 64 divisors (see below), whose sum is σ = 69854400. Its totient is φ = 6488064.

The previous prime is 26691947. The next prime is 26691991. The reversal of 26691990 is 9919662.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26691991) 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 31 ways as a sum of consecutive naturals, for example, 34326 + ... + 35094.

It is an arithmetic number, because the mean of its divisors is an integer number (1091475).

Almost surely, 2^26691990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 26691990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34927200).

26691990 is an abundant number, since it is smaller than the sum of its proper divisors (43162410).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

26691990 is a wasteful number, since it uses less digits than its factorization.

26691990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 881.

The product of its (nonzero) digits is 52488, while the sum is 42.

The square root of 26691990 is about 5166.4291343248. The cubic root of 26691990 is about 298.8548566061.

The spelling of 26691990 in words is "twenty-six million, six hundred ninety-one thousand, nine hundred ninety".