21002215402 has 96 divisors (see below), whose sum is σ = 39140855424. Its totient is φ = 8273664000.

The previous prime is 21002215387. The next prime is 21002215439. The reversal of 21002215402 is 20451220012.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a self number, because there is not a number n which added to its sum of digits gives 21002215402.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 52374402 + ... + 52374802.

It is an arithmetic number, because the mean of its divisors is an integer number (407717244).

Almost surely, 2^21002215402 is an apocalyptic number.

21002215402 is a deficient number, since it is larger than the sum of its proper divisors (18138640022).

21002215402 is a wasteful number, since it uses less digits than its factorization.

21002215402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 732 (or 713 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

Adding to 21002215402 its reverse (20451220012), we get a palindrome (41453435414).

The spelling of 21002215402 in words is "twenty-one billion, two million, two hundred fifteen thousand, four hundred two".