21457545 has 8 divisors (see below), whose sum is σ = 34332096. Its totient is φ = 11444016.

The previous prime is 21457523. The next prime is 21457603. The reversal of 21457545 is 54575412.

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

It is not a de Polignac number, because 21457545 - 2⁶ = 21457481 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 715237 + ... + 715266.

It is an arithmetic number, because the mean of its divisors is an integer number (4291512).

Almost surely, 2^21457545 is an apocalyptic number.

It is an amenable number.

21457545 is a deficient number, since it is larger than the sum of its proper divisors (12874551).

21457545 is a wasteful number, since it uses less digits than its factorization.

21457545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1430511.

The product of its digits is 28000, while the sum is 33.

The square root of 21457545 is about 4632.2289451192. The cubic root of 21457545 is about 277.8817406705.

The spelling of 21457545 in words is "twenty-one million, four hundred fifty-seven thousand, five hundred forty-five".