72121801 has 2 divisors, whose sum is σ = 72121802. Its totient is φ = 72121800.

The previous prime is 72121787. The next prime is 72121807. The reversal of 72121801 is 10812127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59305401 + 12816400 = 7701^2 + 3580^2 .

It is an emirp because it is prime and its reverse (10812127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72121801 - 2¹¹ = 72119753 is a prime.

It is not a weakly prime, because it can be changed into another prime (72121807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36060900 + 36060901.

It is an arithmetic number, because the mean of its divisors is an integer number (36060901).

Almost surely, 2^72121801 is an apocalyptic number.

It is an amenable number.

72121801 is a deficient number, since it is larger than the sum of its proper divisors (1).

72121801 is an equidigital number, since it uses as much as digits as its factorization.

72121801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 72121801 is about 8492.4555341786. The cubic root of 72121801 is about 416.2512216084.

Adding to 72121801 its reverse (10812127), we get a palindrome (82933928).

It can be divided in two parts, 721 and 21801, that added together give a palindrome (22522).

The spelling of 72121801 in words is "seventy-two million, one hundred twenty-one thousand, eight hundred one".