47136821 has 4 divisors (see below), whose sum is σ = 49186272. Its totient is φ = 45087372.

The previous prime is 47136809. The next prime is 47136857. The reversal of 47136821 is 12863174.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 47136821 - 2¹⁸ = 46874677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (47136521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1024691 + ... + 1024736.

It is an arithmetic number, because the mean of its divisors is an integer number (12296568).

Almost surely, 2^47136821 is an apocalyptic number.

It is an amenable number.

47136821 is a deficient number, since it is larger than the sum of its proper divisors (2049451).

47136821 is a wasteful number, since it uses less digits than its factorization.

47136821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2049450.

The product of its digits is 8064, while the sum is 32.

The square root of 47136821 is about 6865.6260457441. The cubic root of 47136821 is about 361.2324554164.

Adding to 47136821 its reverse (12863174), we get a palindrome (59999995).

The spelling of 47136821 in words is "forty-seven million, one hundred thirty-six thousand, eight hundred twenty-one".