81438238 has 16 divisors (see below), whose sum is σ = 140193504. Its totient is φ = 34755840.

The previous prime is 81438229. The next prime is 81438281. The reversal of 81438238 is 83283418.

It is a junction number, because it is equal to n+sod(n) for n = 81438197 and 81438206.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8695 + ... + 15442.

It is an arithmetic number, because the mean of its divisors is an integer number (8762094).

Almost surely, 2^81438238 is an apocalyptic number.

81438238 is a deficient number, since it is larger than the sum of its proper divisors (58755266).

81438238 is a wasteful number, since it uses less digits than its factorization.

81438238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24387.

The product of its digits is 36864, while the sum is 37.

The square root of 81438238 is about 9024.3137135186. The cubic root of 81438238 is about 433.4537749366.

The spelling of 81438238 in words is "eighty-one million, four hundred thirty-eight thousand, two hundred thirty-eight".