21004241506 has 16 divisors (see below), whose sum is σ = 33432066360. Its totient is φ = 9862900480.

The previous prime is 21004241501. The next prime is 21004241507. The reversal of 21004241506 is 60514240012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 17395235881 + 3609005625 = 131891^2 + 60075^2 .

It is a super-2 number, since 2×21004241506² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21004241501) 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, 654361 + ... + 685708.

Almost surely, 2^21004241506 is an apocalyptic number.

21004241506 is a deficient number, since it is larger than the sum of its proper divisors (12427824854).

21004241506 is a wasteful number, since it uses less digits than its factorization.

21004241506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1340549.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21004241506 its reverse (60514240012), we get a palindrome (81518481518).

The spelling of 21004241506 in words is "twenty-one billion, four million, two hundred forty-one thousand, five hundred six".