81372029 has 6 divisors (see below), whose sum is σ = 82029150. Its totient is φ = 80716536.

The previous prime is 81372023. The next prime is 81372037. The reversal of 81372029 is 92027318.

It can be written as a sum of positive squares in only one way, i.e., 54612100 + 26759929 = 7390^2 + 5173^2 .

It is a de Polignac number, because none of the positive numbers 2^k-81372029 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81371986 and 81372004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81372023) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 109742 + ... + 110480.

It is an arithmetic number, because the mean of its divisors is an integer number (13671525).

Almost surely, 2^81372029 is an apocalyptic number.

It is an amenable number.

81372029 is a deficient number, since it is larger than the sum of its proper divisors (657121).

81372029 is an frugal number, since it uses more digits than its factorization.

81372029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1627 (or 888 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 81372029 is about 9020.6446000272. The cubic root of 81372029 is about 433.3362776263.

The spelling of 81372029 in words is "eighty-one million, three hundred seventy-two thousand, twenty-nine".