81420351 has 4 divisors (see below), whose sum is σ = 108560472. Its totient is φ = 54280232.

The previous prime is 81420337. The next prime is 81420379. The reversal of 81420351 is 15302418.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81420351 - 2¹⁴ = 81403967 is a prime.

It is a super-3 number, since 3×81420351³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81420751) 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, 13570056 + ... + 13570061.

It is an arithmetic number, because the mean of its divisors is an integer number (27140118).

Almost surely, 2^81420351 is an apocalyptic number.

81420351 is a deficient number, since it is larger than the sum of its proper divisors (27140121).

81420351 is a wasteful number, since it uses less digits than its factorization.

81420351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27140120.

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 81420351 is about 9023.3226142037. The cubic root of 81420351 is about 433.4220381851.

Adding to 81420351 its reverse (15302418), we get a palindrome (96722769).

The spelling of 81420351 in words is "eighty-one million, four hundred twenty thousand, three hundred fifty-one".