47921781 has 8 divisors (see below), whose sum is σ = 67258720. Its totient is φ = 30266352.

The previous prime is 47921777. The next prime is 47921789. The reversal of 47921781 is 18712974.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 47921781 - 2² = 47921777 is a prime.

It is a super-2 number, since 2×47921781² = 4592994188423922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (47921789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 420310 + ... + 420423.

It is an arithmetic number, because the mean of its divisors is an integer number (8407340).

Almost surely, 2^47921781 is an apocalyptic number.

It is an amenable number.

47921781 is a deficient number, since it is larger than the sum of its proper divisors (19336939).

47921781 is a wasteful number, since it uses less digits than its factorization.

47921781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840755.

The product of its digits is 28224, while the sum is 39.

The square root of 47921781 is about 6922.5559586037. Note that the first 3 decimals coincide. The cubic root of 47921781 is about 363.2266038016.

The spelling of 47921781 in words is "forty-seven million, nine hundred twenty-one thousand, seven hundred eighty-one".