47921257 has 4 divisors (see below), whose sum is σ = 49467136. Its totient is φ = 46375380.

The previous prime is 47921243. The next prime is 47921261. The reversal of 47921257 is 75212974.

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, and also an emirpimes, since its reverse is a distinct semiprime: 75212974 = 2 ⋅37606487.

It is a de Polignac number, because none of the positive numbers 2^k-47921257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (47921297) 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, 772893 + ... + 772954.

It is an arithmetic number, because the mean of its divisors is an integer number (12366784).

Almost surely, 2^47921257 is an apocalyptic number.

It is an amenable number.

47921257 is a deficient number, since it is larger than the sum of its proper divisors (1545879).

47921257 is a wasteful number, since it uses less digits than its factorization.

47921257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1545878.

The product of its digits is 35280, while the sum is 37.

The square root of 47921257 is about 6922.5181112078. The cubic root of 47921257 is about 363.2252798981.

It can be divided in two parts, 479 and 21257, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 47921257 in words is "forty-seven million, nine hundred twenty-one thousand, two hundred fifty-seven".