21754971 has 18 divisors (see below), whose sum is σ = 36555012. Its totient is φ = 12431160.

The previous prime is 21754961. The next prime is 21754991. The reversal of 21754971 is 17945712.

It is a happy number.

It is not a de Polignac number, because 21754971 - 2⁹ = 21754459 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21754961) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 24225 + ... + 25106.

It is an arithmetic number, because the mean of its divisors is an integer number (2030834).

Almost surely, 2^21754971 is an apocalyptic number.

21754971 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21754971 is a deficient number, since it is larger than the sum of its proper divisors (14800041).

21754971 is a wasteful number, since it uses less digits than its factorization.

21754971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49351 (or 49341 counting only the distinct ones).

The product of its digits is 17640, while the sum is 36.

The square root of 21754971 is about 4664.2224432375. Note that the first 3 decimals coincide. The cubic root of 21754971 is about 279.1597728255.

The spelling of 21754971 in words is "twenty-one million, seven hundred fifty-four thousand, nine hundred seventy-one".