21047481 has 48 divisors (see below), whose sum is σ = 38671360. Its totient is φ = 10730880.

The previous prime is 21047449. The next prime is 21047527. The reversal of 21047481 is 18474012.

It is not a de Polignac number, because 21047481 - 2⁵ = 21047449 is a prime.

It is a super-2 number, since 2×21047481² = 885992912890722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21047401) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 24975 + ... + 25803.

Almost surely, 2^21047481 is an apocalyptic number.

21047481 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21047481 is a deficient number, since it is larger than the sum of its proper divisors (17623879).

21047481 is a wasteful number, since it uses less digits than its factorization.

21047481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 886 (or 883 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 21047481 is about 4587.7533717496. The cubic root of 21047481 is about 276.1001920428.

It can be divided in two parts, 21047 and 481, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 21047481 in words is "twenty-one million, forty-seven thousand, four hundred eighty-one".