21001000402 has 16 divisors (see below), whose sum is σ = 33672868992. Its totient is φ = 9798981280.

The previous prime is 21001000373. The next prime is 21001000403. The reversal of 21001000402 is 20400010012.

It is not an unprimeable number, because it can be changed into a prime (21001000403) 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, 5565718 + ... + 5569489.

It is an arithmetic number, because the mean of its divisors is an integer number (2104554312).

Almost surely, 2^21001000402 is an apocalyptic number.

21001000402 is a deficient number, since it is larger than the sum of its proper divisors (12671868590).

21001000402 is a wasteful number, since it uses less digits than its factorization.

21001000402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11135273.

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21001000402 its reverse (20400010012), we get a palindrome (41401010414).

The spelling of 21001000402 in words is "twenty-one billion, one million, four hundred two", and thus it is an aban number.