21372104 has 32 divisors (see below), whose sum is σ = 43659000. Its totient is φ = 9748992.

The previous prime is 21372103. The next prime is 21372133. The reversal of 21372104 is 40127312.

It can be written as a sum of positive squares in 4 ways, for example, as 15132100 + 6240004 = 3890^2 + 2498^2 .

It is not an unprimeable number, because it can be changed into a prime (21372103) 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, 8102 + ... + 10410.

Almost surely, 2^21372104 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21372104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21829500).

21372104 is an abundant number, since it is smaller than the sum of its proper divisors (22286896).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21372104 is a wasteful number, since it uses less digits than its factorization.

21372104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2417 (or 2413 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21372104 is about 4622.9972961273. The cubic root of 21372104 is about 277.5124210548.

Adding to 21372104 its reverse (40127312), we get a palindrome (61499416).

The spelling of 21372104 in words is "twenty-one million, three hundred seventy-two thousand, one hundred four".