21148457 has 8 divisors (see below), whose sum is σ = 23105280. Its totient is φ = 19197360.

The previous prime is 21148427. The next prime is 21148481. The reversal of 21148457 is 75484112.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21148457 - 2¹⁰ = 21147433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21148427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11144 + ... + 12902.

It is an arithmetic number, because the mean of its divisors is an integer number (2888160).

Almost surely, 2^21148457 is an apocalyptic number.

It is an amenable number.

21148457 is a deficient number, since it is larger than the sum of its proper divisors (1956823).

21148457 is a wasteful number, since it uses less digits than its factorization.

21148457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2863.

The product of its digits is 8960, while the sum is 32.

The square root of 21148457 is about 4598.7451549309. The cubic root of 21148457 is about 276.5410211564.

The spelling of 21148457 in words is "twenty-one million, one hundred forty-eight thousand, four hundred fifty-seven".