26978391001 has 3 divisors (see below), whose sum is σ = 26978555253. Its totient is φ = 26978226750.

The previous prime is 26978390939. The next prime is 26978391007. The reversal of 26978391001 is 10019387962.

It is a happy number.

The square root of 26978391001 is 164251.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 10019387962 = 2 ⋅5009693981.

It is not a de Polignac number, because 26978391001 - 2¹¹ = 26978388953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26978391007) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 82126 + ... + 246376.

It is an arithmetic number, because the mean of its divisors is an integer number (8992851751).

Almost surely, 2^26978391001 is an apocalyptic number.

26978391001 is the 164251-st square number.

26978391001 is the 82126-th centered octagonal number.

It is an amenable number.

26978391001 is a deficient number, since it is larger than the sum of its proper divisors (164252).

26978391001 is an frugal number, since it uses more digits than its factorization.

26978391001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328502 (or 164251 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 46.

The spelling of 26978391001 in words is "twenty-six billion, nine hundred seventy-eight million, three hundred ninety-one thousand, one".