81542380 has 24 divisors (see below), whose sum is σ = 172296432. Its totient is φ = 32415552.

The previous prime is 81542359. The next prime is 81542381. The reversal of 81542380 is 8324518.

It is not an unprimeable number, because it can be changed into a prime (81542381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9247 + ... + 15766.

It is an arithmetic number, because the mean of its divisors is an integer number (7179018).

Almost surely, 2^81542380 is an apocalyptic number.

It is an amenable number.

81542380 is an abundant number, since it is smaller than the sum of its proper divisors (90754052).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81542380 is a wasteful number, since it uses less digits than its factorization.

81542380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25185 (or 25183 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 81542380 is about 9030.0819486868. The cubic root of 81542380 is about 433.6384609679.

Adding to 81542380 its reverse (8324518), we get a palindrome (89866898).

The spelling of 81542380 in words is "eighty-one million, five hundred forty-two thousand, three hundred eighty".