81420190 has 16 divisors (see below), whose sum is σ = 149322528. Its totient is φ = 31953376.

The previous prime is 81420181. The next prime is 81420193. The reversal of 81420190 is 9102418.

It is a happy number.

It is a super-2 number, since 2×81420190² = 13258494679272200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81420193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76282 + ... + 77341.

It is an arithmetic number, because the mean of its divisors is an integer number (9332658).

Almost surely, 2^81420190 is an apocalyptic number.

81420190 is a deficient number, since it is larger than the sum of its proper divisors (67902338).

81420190 is a wasteful number, since it uses less digits than its factorization.

81420190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153683.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 81420190 is about 9023.3136928736. The cubic root of 81420190 is about 433.4217525030.

The spelling of 81420190 in words is "eighty-one million, four hundred twenty thousand, one hundred ninety".