81420101 has 4 divisors (see below), whose sum is σ = 93051552. Its totient is φ = 69788652.

The previous prime is 81420083. The next prime is 81420127. The reversal of 81420101 is 10102418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 10102418 = 2 ⋅5051209.

It is a cyclic number.

It is not a de Polignac number, because 81420101 - 2¹⁸ = 81157957 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81420101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81420181) 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, 5815715 + ... + 5815728.

It is an arithmetic number, because the mean of its divisors is an integer number (23262888).

Almost surely, 2^81420101 is an apocalyptic number.

It is an amenable number.

81420101 is a deficient number, since it is larger than the sum of its proper divisors (11631451).

81420101 is a wasteful number, since it uses less digits than its factorization.

81420101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11631450.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 81420101 is about 9023.3087612028. The cubic root of 81420101 is about 433.4215945793.

Adding to 81420101 its reverse (10102418), we get a palindrome (91522519).

The spelling of 81420101 in words is "eighty-one million, four hundred twenty thousand, one hundred one".