26821997 has 4 divisors (see below), whose sum is σ = 27017916. Its totient is φ = 26626080.

The previous prime is 26821987. The next prime is 26822017. The reversal of 26821997 is 79912862.

It is a happy number.

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 11930116 + 14891881 = 3454^2 + 3859^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26821997 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 (26821987) 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, 97754 + ... + 98027.

It is an arithmetic number, because the mean of its divisors is an integer number (6754479).

Almost surely, 2^26821997 is an apocalyptic number.

It is an amenable number.

26821997 is a deficient number, since it is larger than the sum of its proper divisors (195919).

26821997 is a wasteful number, since it uses less digits than its factorization.

26821997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195918.

The product of its digits is 108864, while the sum is 44.

The square root of 26821997 is about 5178.9957520739. The cubic root of 26821997 is about 299.3392755084.

Adding to 26821997 its sum of digits (44), we get a square (26822041 = 5179²).

The spelling of 26821997 in words is "twenty-six million, eight hundred twenty-one thousand, nine hundred ninety-seven".