21000420982 has 4 divisors (see below), whose sum is σ = 31500631476. Its totient is φ = 10500210490.

The previous prime is 21000420979. The next prime is 21000420983. The reversal of 21000420982 is 28902400012.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21000420982.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000420983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5250105244 + ... + 5250105247.

It is an arithmetic number, because the mean of its divisors is an integer number (7875157869).

Almost surely, 2^21000420982 is an apocalyptic number.

21000420982 is a deficient number, since it is larger than the sum of its proper divisors (10500210494).

21000420982 is a wasteful number, since it uses less digits than its factorization.

21000420982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10500210493.

The product of its (nonzero) digits is 2304, while the sum is 28.

Adding to 21000420982 its reverse (28902400012), we get a palindrome (49902820994).

The spelling of 21000420982 in words is "twenty-one billion, four hundred twenty thousand, nine hundred eighty-two".