47578921 has 4 divisors (see below), whose sum is σ = 51238852. Its totient is φ = 43918992.

The previous prime is 47578919. The next prime is 47578931. The reversal of 47578921 is 12987574.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2205225 + 45373696 = 1485^2 + 6736^2 .

It is not a de Polignac number, because 47578921 - 2¹ = 47578919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (47578931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1829946 + ... + 1829971.

It is an arithmetic number, because the mean of its divisors is an integer number (12809713).

Almost surely, 2^47578921 is an apocalyptic number.

It is an amenable number.

47578921 is a deficient number, since it is larger than the sum of its proper divisors (3659931).

47578921 is a wasteful number, since it uses less digits than its factorization.

47578921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3659930.

The product of its digits is 141120, while the sum is 43.

The square root of 47578921 is about 6897.7475308973. The cubic root of 47578921 is about 362.3582856285.

The spelling of 47578921 in words is "forty-seven million, five hundred seventy-eight thousand, nine hundred twenty-one".