21624104 has 8 divisors (see below), whose sum is σ = 40545210. Its totient is φ = 10812048.

The previous prime is 21624101. The next prime is 21624107. The reversal of 21624104 is 40142612.

It is an interprime number because it is at equal distance from previous prime (21624101) and next prime (21624107).

It can be written as a sum of positive squares in only one way, i.e., 17222500 + 4401604 = 4150^2 + 2098^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21624101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1351499 + ... + 1351514.

Almost surely, 2^21624104 is an apocalyptic number.

It is an amenable number.

21624104 is a deficient number, since it is larger than the sum of its proper divisors (18921106).

21624104 is a wasteful number, since it uses less digits than its factorization.

21624104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2703019 (or 2703015 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 21624104 is about 4650.1724699198. The cubic root of 21624104 is about 278.5988848928.

Adding to 21624104 its reverse (40142612), we get a palindrome (61766716).

The spelling of 21624104 in words is "twenty-one million, six hundred twenty-four thousand, one hundred four".