81438190 has 8 divisors (see below), whose sum is σ = 146588760. Its totient is φ = 32575272.

The previous prime is 81438179. The next prime is 81438191. The reversal of 81438190 is 9183418.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×81438190² = 13264357580952200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81438191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4071900 + ... + 4071919.

It is an arithmetic number, because the mean of its divisors is an integer number (18323595).

Almost surely, 2^81438190 is an apocalyptic number.

81438190 is a deficient number, since it is larger than the sum of its proper divisors (65150570).

81438190 is a wasteful number, since it uses less digits than its factorization.

81438190 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8143826.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 81438190 is about 9024.3110540362. The cubic root of 81438190 is about 433.4536897768.

The spelling of 81438190 in words is "eighty-one million, four hundred thirty-eight thousand, one hundred ninety".