81621045 has 48 divisors (see below), whose sum is σ = 155361024. Its totient is φ = 39312000.

The previous prime is 81621031. The next prime is 81621049. The reversal of 81621045 is 54012618.

It is not a de Polignac number, because 81621045 - 2¹¹ = 81618997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81621049) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 89140 + ... + 90050.

It is an arithmetic number, because the mean of its divisors is an integer number (3236688).

Almost surely, 2^81621045 is an apocalyptic number.

It is an amenable number.

81621045 is a deficient number, since it is larger than the sum of its proper divisors (73739979).

81621045 is a wasteful number, since it uses less digits than its factorization.

81621045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1114 (or 1111 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 81621045 is about 9034.4366177421. The cubic root of 81621045 is about 433.7778617144. Note that the first 3 decimals are identical.

It can be divided in two parts, 81 and 621045, that added together give a palindrome (621126).

The spelling of 81621045 in words is "eighty-one million, six hundred twenty-one thousand, forty-five".