81155420 has 24 divisors (see below), whose sum is σ = 170628864. Its totient is φ = 32423616.

The previous prime is 81155411. The next prime is 81155423. The reversal of 81155420 is 2455118.

It is a self number, because there is not a number n which added to its sum of digits gives 81155420.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81155423) 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, 19874 + ... + 23606.

It is an arithmetic number, because the mean of its divisors is an integer number (7109536).

Almost surely, 2^81155420 is an apocalyptic number.

It is an amenable number.

81155420 is an abundant number, since it is smaller than the sum of its proper divisors (89473444).

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

81155420 is a wasteful number, since it uses less digits than its factorization.

81155420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4829 (or 4827 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 81155420 is about 9008.6303065449. The cubic root of 81155420 is about 432.9514281469.

The spelling of 81155420 in words is "eighty-one million, one hundred fifty-five thousand, four hundred twenty".