81225020 has 12 divisors (see below), whose sum is σ = 170572584. Its totient is φ = 32490000.

The previous prime is 81225013. The next prime is 81225037. The reversal of 81225020 is 2052218.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 4061251 = 81225020 / (8 + 1 + 2 + 2 + 5 + 0 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 81224983 and 81225001.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2030606 + ... + 2030645.

It is an arithmetic number, because the mean of its divisors is an integer number (14214382).

Almost surely, 2^81225020 is an apocalyptic number.

It is an amenable number.

81225020 is an abundant number, since it is smaller than the sum of its proper divisors (89347564).

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

81225020 is a wasteful number, since it uses less digits than its factorization.

81225020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4061260 (or 4061258 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 81225020 is about 9012.4924410509. The cubic root of 81225020 is about 433.0751611406.

Adding to 81225020 its reverse (2052218), we get a palindrome (83277238).

The spelling of 81225020 in words is "eighty-one million, two hundred twenty-five thousand, twenty".