81021545 has 16 divisors (see below), whose sum is σ = 106505280. Its totient is φ = 58680000.

The previous prime is 81021539. The next prime is 81021547. The reversal of 81021545 is 54512018.

It is not a de Polignac number, because 81021545 - 2¹² = 81017449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81021547) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10871 + ... + 16739.

It is an arithmetic number, because the mean of its divisors is an integer number (6656580).

Almost surely, 2^81021545 is an apocalyptic number.

It is an amenable number.

81021545 is a deficient number, since it is larger than the sum of its proper divisors (25483735).

81021545 is a wasteful number, since it uses less digits than its factorization.

81021545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6136.

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

The square root of 81021545 is about 9001.1968648619. The cubic root of 81021545 is about 432.7132297495.

The spelling of 81021545 in words is "eighty-one million, twenty-one thousand, five hundred forty-five".