81506029 has 8 divisors (see below), whose sum is σ = 93595680. Its totient is φ = 70196400.

The previous prime is 81505999. The next prime is 81506053. The reversal of 81506029 is 92060518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81506029 - 2⁷ = 81505901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81506059) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194782 + ... + 195199.

It is an arithmetic number, because the mean of its divisors is an integer number (11699460).

Almost surely, 2^81506029 is an apocalyptic number.

It is an amenable number.

81506029 is a deficient number, since it is larger than the sum of its proper divisors (12089651).

81506029 is a wasteful number, since it uses less digits than its factorization.

81506029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390011.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 81506029 is about 9028.0689518856. The cubic root of 81506029 is about 433.5740137662.

The spelling of 81506029 in words is "eighty-one million, five hundred six thousand, twenty-nine".