81354780 has 120 divisors (see below), whose sum is σ = 274915872. Its totient is φ = 20020608.

The previous prime is 81354761. The next prime is 81354781. The reversal of 81354780 is 8745318.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81354781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 19129 + ... + 22991.

Almost surely, 2^81354780 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81354780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137457936).

81354780 is an abundant number, since it is smaller than the sum of its proper divisors (193561092).

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

81354780 is a wasteful number, since it uses less digits than its factorization.

81354780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3897 (or 3886 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 81354780 is about 9019.6884646866. The cubic root of 81354780 is about 433.3056563520.

The spelling of 81354780 in words is "eighty-one million, three hundred fifty-four thousand, seven hundred eighty".