81587069 has 4 divisors (see below), whose sum is σ = 81621696. Its totient is φ = 81552444.

The previous prime is 81587057. The next prime is 81587081. The reversal of 81587069 is 96078518.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 96078518 = 2 ⋅48039259.

It is an interprime number because it is at equal distance from previous prime (81587057) and next prime (81587081).

It is a cyclic number.

It is not a de Polignac number, because 81587069 - 2⁴ = 81587053 is a prime.

It is a super-2 number, since 2×81587069² = 13312899656021522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81587269) 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, 13499 + ... + 18584.

It is an arithmetic number, because the mean of its divisors is an integer number (20405424).

Almost surely, 2^81587069 is an apocalyptic number.

It is an amenable number.

81587069 is a deficient number, since it is larger than the sum of its proper divisors (34627).

81587069 is a wasteful number, since it uses less digits than its factorization.

81587069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34626.

The product of its (nonzero) digits is 120960, while the sum is 44.

The square root of 81587069 is about 9032.5560612708. The cubic root of 81587069 is about 433.7176644859.

The spelling of 81587069 in words is "eighty-one million, five hundred eighty-seven thousand, sixty-nine".