21290533 has 8 divisors (see below), whose sum is σ = 23338656. Its totient is φ = 19261200.

The previous prime is 21290531. The next prime is 21290537. The reversal of 21290533 is 33509212.

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 21290533 - 2¹ = 21290531 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21290498 and 21290507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21290531) 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, 2266 + ... + 6907.

It is an arithmetic number, because the mean of its divisors is an integer number (2917332).

Almost surely, 2^21290533 is an apocalyptic number.

It is an amenable number.

21290533 is a deficient number, since it is larger than the sum of its proper divisors (2048123).

21290533 is a wasteful number, since it uses less digits than its factorization.

21290533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9395.

The product of its (nonzero) digits is 1620, while the sum is 25.

The square root of 21290533 is about 4614.1665552947. The cubic root of 21290533 is about 277.1589099787.

Adding to 21290533 its reverse (33509212), we get a palindrome (54799745).

The spelling of 21290533 in words is "twenty-one million, two hundred ninety thousand, five hundred thirty-three".