81154009 has 4 divisors (see below), whose sum is σ = 81942016. Its totient is φ = 80366004.

The previous prime is 81153967. The next prime is 81154013. The reversal of 81154009 is 90045118.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 81154009 - 2¹⁷ = 81022937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81154019) 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, 393849 + ... + 394054.

It is an arithmetic number, because the mean of its divisors is an integer number (20485504).

Almost surely, 2^81154009 is an apocalyptic number.

It is an amenable number.

81154009 is a deficient number, since it is larger than the sum of its proper divisors (788007).

81154009 is a wasteful number, since it uses less digits than its factorization.

81154009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 788006.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 81154009 is about 9008.5519924125. The cubic root of 81154009 is about 432.9489189778.

The spelling of 81154009 in words is "eighty-one million, one hundred fifty-four thousand, nine".