21223501 has 8 divisors (see below), whose sum is σ = 22900640. Its totient is φ = 19552752.

The previous prime is 21223487. The next prime is 21223507. The reversal of 21223501 is 10532212.

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 21223501 - 2¹³ = 21215309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21223507) 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, 7090 + ... + 9628.

It is an arithmetic number, because the mean of its divisors is an integer number (2862580).

Almost surely, 2^21223501 is an apocalyptic number.

It is an amenable number.

21223501 is a deficient number, since it is larger than the sum of its proper divisors (1677139).

21223501 is a wasteful number, since it uses less digits than its factorization.

21223501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3195.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21223501 is about 4606.8971119399. The cubic root of 21223501 is about 276.8677312966.

Adding to 21223501 its reverse (10532212), we get a palindrome (31755713).

The spelling of 21223501 in words is "twenty-one million, two hundred twenty-three thousand, five hundred one".