81393501 has 16 divisors (see below), whose sum is σ = 131324544. Its totient is φ = 43774464.

The previous prime is 81393457. The next prime is 81393523. The reversal of 81393501 is 10539318.

It is a happy number.

It is not a de Polignac number, because 81393501 - 2¹³ = 81385309 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81393551) 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, 113640 + ... + 114353.

It is an arithmetic number, because the mean of its divisors is an integer number (8207784).

Almost surely, 2^81393501 is an apocalyptic number.

It is an amenable number.

81393501 is a deficient number, since it is larger than the sum of its proper divisors (49931043).

81393501 is a wasteful number, since it uses less digits than its factorization.

81393501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228020.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 81393501 is about 9021.8346803741. The cubic root of 81393501 is about 433.3743897326.

The spelling of 81393501 in words is "eighty-one million, three hundred ninety-three thousand, five hundred one".