81215238 has 16 divisors (see below), whose sum is σ = 174925296. Its totient is φ = 24989280.

The previous prime is 81215237. The next prime is 81215269. The reversal of 81215238 is 83251218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81215237) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 520533 + ... + 520688.

It is an arithmetic number, because the mean of its divisors is an integer number (10932831).

Almost surely, 2^81215238 is an apocalyptic number.

81215238 is an abundant number, since it is smaller than the sum of its proper divisors (93710058).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81215238 is a wasteful number, since it uses less digits than its factorization.

81215238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1041239.

The product of its digits is 3840, while the sum is 30.

The square root of 81215238 is about 9011.9497335482. The cubic root of 81215238 is about 433.0577752362.

The spelling of 81215238 in words is "eighty-one million, two hundred fifteen thousand, two hundred thirty-eight".