81589557 has 24 divisors (see below), whose sum is σ = 130917600. Its totient is φ = 45012576.

The previous prime is 81589537. The next prime is 81589559. The reversal of 81589557 is 75598518.

It is not a de Polignac number, because 81589557 - 2⁷ = 81589429 is a prime.

It is a super-2 number, since 2×81589557² = 13313711622912498, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81589559) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5307 + ... + 13832.

It is an arithmetic number, because the mean of its divisors is an integer number (5454900).

Almost surely, 2^81589557 is an apocalyptic number.

81589557 is a gapful number since it is divisible by the number (87) formed by its first and last digit.

It is an amenable number.

81589557 is a deficient number, since it is larger than the sum of its proper divisors (49328043).

81589557 is a wasteful number, since it uses less digits than its factorization.

81589557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19185 (or 19178 counting only the distinct ones).

The product of its digits is 504000, while the sum is 48.

The square root of 81589557 is about 9032.6937842484. The cubic root of 81589557 is about 433.7220731853.

The spelling of 81589557 in words is "eighty-one million, five hundred eighty-nine thousand, five hundred fifty-seven".