81154980 has 48 divisors (see below), whose sum is σ = 252483840. Its totient is φ = 21641184.

The previous prime is 81154979. The next prime is 81154981. The reversal of 81154980 is 8945118.

It is an interprime number because it is at equal distance from previous prime (81154979) and next prime (81154981).

It is a super-2 number, since 2×81154980² = 13172261557600800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (81154981) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 74604 + ... + 75683.

It is an arithmetic number, because the mean of its divisors is an integer number (5260080).

Almost surely, 2^81154980 is an apocalyptic number.

It is an amenable number.

81154980 is an abundant number, since it is smaller than the sum of its proper divisors (171328860).

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

81154980 is a wasteful number, since it uses less digits than its factorization.

81154980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150305 (or 150297 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 81154980 is about 9008.6058854853. The cubic root of 81154980 is about 432.9506457018.

The spelling of 81154980 in words is "eighty-one million, one hundred fifty-four thousand, nine hundred eighty".