26021238721 has 9 divisors (see below), whose sum is σ = 26308084131. Its totient is φ = 25737492672.

The previous prime is 26021238647. The next prime is 26021238731. The reversal of 26021238721 is 12783212062.

It is a happy number.

The square root of 26021238721 is 161311.

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

It can be written as a sum of positive squares in only one way, i.e., 11684529025 + 14336709696 = 108095^2 + 119736^2 .

It is not a de Polignac number, because 26021238721 - 2¹⁵ = 26021205953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26021238731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 15646336 + ... + 15647998.

It is an arithmetic number, because the mean of its divisors is an integer number (2923120459).

Almost surely, 2^26021238721 is an apocalyptic number.

26021238721 is the 161311-st square number.

26021238721 is the 80656-th centered octagonal number.

It is an amenable number.

26021238721 is a deficient number, since it is larger than the sum of its proper divisors (286845410).

26021238721 is an frugal number, since it uses more digits than its factorization.

26021238721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3520 (or 1760 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

The spelling of 26021238721 in words is "twenty-six billion, twenty-one million, two hundred thirty-eight thousand, seven hundred twenty-one".