21002215411 has 4 divisors (see below), whose sum is σ = 21047773824. Its totient is φ = 20956657000.

The previous prime is 21002215387. The next prime is 21002215439. The reversal of 21002215411 is 11451220012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21002215411 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002215441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22778515 + ... + 22779436.

It is an arithmetic number, because the mean of its divisors is an integer number (5261943456).

Almost surely, 2^21002215411 is an apocalyptic number.

21002215411 is a deficient number, since it is larger than the sum of its proper divisors (45558413).

21002215411 is an equidigital number, since it uses as much as digits as its factorization.

21002215411 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45558412.

The product of its (nonzero) digits is 160, while the sum is 19.

Adding to 21002215411 its reverse (11451220012), we get a palindrome (32453435423).

The spelling of 21002215411 in words is "twenty-one billion, two million, two hundred fifteen thousand, four hundred eleven".