72187771 has 2 divisors, whose sum is σ = 72187772. Its totient is φ = 72187770.

The previous prime is 72187769. The next prime is 72187781. The reversal of 72187771 is 17778127.

It is a weak prime.

It is an emirp because it is prime and its reverse (17778127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72187771 - 2¹ = 72187769 is a prime.

It is a super-2 number, since 2×72187771² = 10422148563896882, which contains 22 as substring.

Together with 72187769, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (72187711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36093885 + 36093886.

It is an arithmetic number, because the mean of its divisors is an integer number (36093886).

Almost surely, 2^72187771 is an apocalyptic number.

72187771 is a deficient number, since it is larger than the sum of its proper divisors (1).

72187771 is an equidigital number, since it uses as much as digits as its factorization.

72187771 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38416, while the sum is 40.

The square root of 72187771 is about 8496.3386820442. The cubic root of 72187771 is about 416.3780982918.

The spelling of 72187771 in words is "seventy-two million, one hundred eighty-seven thousand, seven hundred seventy-one".