21004102402 has 4 divisors (see below), whose sum is σ = 31506153606. Its totient is φ = 10502051200.

The previous prime is 21004102381. The next prime is 21004102403. The reversal of 21004102402 is 20420140012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 14791667641 + 6212434761 = 121621^2 + 78819^2 .

It is not an unprimeable number, because it can be changed into a prime (21004102403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5251025599 + ... + 5251025602.

Almost surely, 2^21004102402 is an apocalyptic number.

21004102402 is a deficient number, since it is larger than the sum of its proper divisors (10502051204).

21004102402 is a wasteful number, since it uses less digits than its factorization.

21004102402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10502051203.

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21004102402 its reverse (20420140012), we get a palindrome (41424242414).

The spelling of 21004102402 in words is "twenty-one billion, four million, one hundred two thousand, four hundred two".