72137818 has 4 divisors (see below), whose sum is σ = 108206730. Its totient is φ = 36068908.

The previous prime is 72137743. The next prime is 72137881. The reversal of 72137818 is 81873127.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 67354849 + 4782969 = 8207^2 + 2187^2 .

It is a super-2 number, since 2×72137818² = 10407729571602248, which contains 22 as substring.

It is an unprimeable number.

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, 18034453 + ... + 18034456.

Almost surely, 2^72137818 is an apocalyptic number.

72137818 is a deficient number, since it is larger than the sum of its proper divisors (36068912).

72137818 is a wasteful number, since it uses less digits than its factorization.

72137818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36068911.

The product of its digits is 18816, while the sum is 37.

The square root of 72137818 is about 8493.3984953021. The cubic root of 72137818 is about 416.2820333844.

The spelling of 72137818 in words is "seventy-two million, one hundred thirty-seven thousand, eight hundred eighteen".