81029931 has 8 divisors (see below), whose sum is σ = 110552640. Its totient is φ = 52763592.

The previous prime is 81029929. The next prime is 81029933. The reversal of 81029931 is 13992018.

It is an interprime number because it is at equal distance from previous prime (81029929) and next prime (81029933).

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

It is not a de Polignac number, because 81029931 - 2¹ = 81029929 is a prime.

It is a super-2 number, since 2×81029931² = 13131699435729522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81029892 and 81029901.

It is not an unprimeable number, because it can be changed into a prime (81029933) 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, 313941 + ... + 314198.

It is an arithmetic number, because the mean of its divisors is an integer number (13819080).

Almost surely, 2^81029931 is an apocalyptic number.

81029931 is a deficient number, since it is larger than the sum of its proper divisors (29522709).

81029931 is a wasteful number, since it uses less digits than its factorization.

81029931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 628185.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 81029931 is about 9001.6626797498. The cubic root of 81029931 is about 432.7281583217.

The spelling of 81029931 in words is "eighty-one million, twenty-nine thousand, nine hundred thirty-one".