21024661 has 8 divisors (see below), whose sum is σ = 24058944. Its totient is φ = 17998080.

The previous prime is 21024643. The next prime is 21024743. The reversal of 21024661 is 16642012.

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 21024661 - 2⁵ = 21024629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6261 + ... + 9013.

It is an arithmetic number, because the mean of its divisors is an integer number (3007368).

Almost surely, 2^21024661 is an apocalyptic number.

It is an amenable number.

21024661 is a deficient number, since it is larger than the sum of its proper divisors (3034283).

21024661 is a wasteful number, since it uses less digits than its factorization.

21024661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3851.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21024661 is about 4585.2656411597. The cubic root of 21024661 is about 276.0003719452. Note that the first 3 decimals are identical.

Adding to 21024661 its reverse (16642012), we get a palindrome (37666673).

The spelling of 21024661 in words is "twenty-one million, twenty-four thousand, six hundred sixty-one".