72615421 has 2 divisors, whose sum is σ = 72615422. Its totient is φ = 72615420.

The previous prime is 72615419. The next prime is 72615427. The reversal of 72615421 is 12451627.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37687321 + 34928100 = 6139^2 + 5910^2 .

It is an emirp because it is prime and its reverse (12451627) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72615421 - 2¹ = 72615419 is a prime.

Together with 72615419, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 72615421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72615427) 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 as a sum of consecutive naturals, namely, 36307710 + 36307711.

It is an arithmetic number, because the mean of its divisors is an integer number (36307711).

Almost surely, 2^72615421 is an apocalyptic number.

It is an amenable number.

72615421 is a deficient number, since it is larger than the sum of its proper divisors (1).

72615421 is an equidigital number, since it uses as much as digits as its factorization.

72615421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3360, while the sum is 28.

The square root of 72615421 is about 8521.4682420344. The cubic root of 72615421 is about 417.1987064494.

The spelling of 72615421 in words is "seventy-two million, six hundred fifteen thousand, four hundred twenty-one".