81632385 has 36 divisors (see below), whose sum is σ = 150332988. Its totient is φ = 40969728.

The previous prime is 81632371. The next prime is 81632399. The reversal of 81632385 is 58323618.

It is an interprime number because it is at equal distance from previous prime (81632371) and next prime (81632399).

It can be written as a sum of positive squares in 6 ways, for example, as 21678336 + 59954049 = 4656^2 + 7743^2 .

It is not a de Polignac number, because 81632385 - 2¹¹ = 81630337 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 9867 + ... + 16143.

Almost surely, 2^81632385 is an apocalyptic number.

81632385 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

81632385 is a deficient number, since it is larger than the sum of its proper divisors (68700603).

81632385 is a wasteful number, since it uses less digits than its factorization.

81632385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6322 (or 6302 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 81632385 is about 9035.0641945700. The cubic root of 81632385 is about 433.7979497246.

The spelling of 81632385 in words is "eighty-one million, six hundred thirty-two thousand, three hundred eighty-five".