81438670 has 32 divisors (see below), whose sum is σ = 160574400. Its totient is φ = 29600256.

The previous prime is 81438667. The next prime is 81438673. The reversal of 81438670 is 7683418.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81438667) and next prime (81438673).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81438673) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3330 + ... + 13189.

It is an arithmetic number, because the mean of its divisors is an integer number (5017950).

Almost surely, 2^81438670 is an apocalyptic number.

81438670 is a deficient number, since it is larger than the sum of its proper divisors (79135730).

81438670 is a wasteful number, since it uses less digits than its factorization.

81438670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16572.

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 81438670 is about 9024.3376488250. The cubic root of 81438670 is about 433.4545413731.

The spelling of 81438670 in words is "eighty-one million, four hundred thirty-eight thousand, six hundred seventy".