21004030402 has 4 divisors (see below), whose sum is σ = 31506045606. Its totient is φ = 10502015200.

The previous prime is 21004030391. The next prime is 21004030423. The reversal of 21004030402 is 20403040012.

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., 20984129881 + 19900521 = 144859^2 + 4461^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5251007599 + ... + 5251007602.

Almost surely, 2^21004030402 is an apocalyptic number.

21004030402 is a deficient number, since it is larger than the sum of its proper divisors (10502015204).

21004030402 is a wasteful number, since it uses less digits than its factorization.

21004030402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10502015203.

The product of its (nonzero) digits is 192, while the sum is 16.

Adding to 21004030402 its reverse (20403040012), we get a palindrome (41407070414).

The spelling of 21004030402 in words is "twenty-one billion, four million, thirty thousand, four hundred two".