81081407 has 4 divisors (see below), whose sum is σ = 88452456. Its totient is φ = 73710360.

The previous prime is 81081391. The next prime is 81081409. The reversal of 81081407 is 70418018.

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 81081407 - 2⁴ = 81081391 is a prime.

It is a super-2 number, since 2×81081407² = 13148389122199298, which contains 22 as substring.

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 81081407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81081409) 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, 3685508 + ... + 3685529.

It is an arithmetic number, because the mean of its divisors is an integer number (22113114).

Almost surely, 2^81081407 is an apocalyptic number.

81081407 is a deficient number, since it is larger than the sum of its proper divisors (7371049).

81081407 is a wasteful number, since it uses less digits than its factorization.

81081407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7371048.

The product of its (nonzero) digits is 1792, while the sum is 29.

The square root of 81081407 is about 9004.5214753478. The cubic root of 81081407 is about 432.8197722029.

The spelling of 81081407 in words is "eighty-one million, eighty-one thousand, four hundred seven".