81279437 has 4 divisors (see below), whose sum is σ = 81337056. Its totient is φ = 81221820.

The previous prime is 81279413. The next prime is 81279449. The reversal of 81279437 is 73497218.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81279437 - 2²² = 77085133 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81279394 and 81279403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81279467) 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, 26639 + ... + 29532.

It is an arithmetic number, because the mean of its divisors is an integer number (20334264).

Almost surely, 2^81279437 is an apocalyptic number.

It is an amenable number.

81279437 is a deficient number, since it is larger than the sum of its proper divisors (57619).

81279437 is a wasteful number, since it uses less digits than its factorization.

81279437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57618.

The product of its digits is 84672, while the sum is 41.

The square root of 81279437 is about 9015.5109117565. The cubic root of 81279437 is about 433.1718529816.

The spelling of 81279437 in words is "eighty-one million, two hundred seventy-nine thousand, four hundred thirty-seven".