74721645 has 48 divisors (see below), whose sum is σ = 133241472. Its totient is φ = 38724480.

The previous prime is 74721643. The next prime is 74721697. The reversal of 74721645 is 54612747.

74721645 is a `hidden beast` number, since 7 + 4 + 7 + 2 + 1 + 645 = 666.

It is not a de Polignac number, because 74721645 - 2¹ = 74721643 is a prime.

It is a super-3 number, since 3×74721645³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (74721643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 447352 + ... + 447518.

It is an arithmetic number, because the mean of its divisors is an integer number (2775864).

Almost surely, 2^74721645 is an apocalyptic number.

It is an amenable number.

74721645 is a deficient number, since it is larger than the sum of its proper divisors (58519827).

74721645 is a wasteful number, since it uses less digits than its factorization.

74721645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402 (or 399 counting only the distinct ones).

The product of its digits is 47040, while the sum is 36.

The square root of 74721645 is about 8644.1682653683. The cubic root of 74721645 is about 421.1939665480.

The spelling of 74721645 in words is "seventy-four million, seven hundred twenty-one thousand, six hundred forty-five".