81241407 has 32 divisors (see below), whose sum is σ = 131846400. Its totient is φ = 49134816.

The previous prime is 81241403. The next prime is 81241409. The reversal of 81241407 is 70414218.

It is not a de Polignac number, because 81241407 - 2² = 81241403 is a prime.

It is a super-2 number, since 2×81241407² = 13200332422679298, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81241403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18748 + ... + 22670.

It is an arithmetic number, because the mean of its divisors is an integer number (4120200).

Almost surely, 2^81241407 is an apocalyptic number.

81241407 is a deficient number, since it is larger than the sum of its proper divisors (50604993).

81241407 is a wasteful number, since it uses less digits than its factorization.

81241407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4004 (or 3998 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 81241407 is about 9013.4015221780. The cubic root of 81241407 is about 433.1042832242.

The spelling of 81241407 in words is "eighty-one million, two hundred forty-one thousand, four hundred seven".