21002222554 has 4 divisors (see below), whose sum is σ = 31503333834. Its totient is φ = 10501111276.

The previous prime is 21002222551. The next prime is 21002222573. The reversal of 21002222554 is 45522220012.

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., 19506312225 + 1495910329 = 139665^2 + 38677^2 .

It is not an unprimeable number, because it can be changed into a prime (21002222551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5250555637 + ... + 5250555640.

Almost surely, 2^21002222554 is an apocalyptic number.

21002222554 is a deficient number, since it is larger than the sum of its proper divisors (10501111280).

21002222554 is a wasteful number, since it uses less digits than its factorization.

21002222554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10501111279.

The product of its (nonzero) digits is 3200, while the sum is 25.

Adding to 21002222554 its reverse (45522220012), we get a palindrome (66524442566).

The spelling of 21002222554 in words is "twenty-one billion, two million, two hundred twenty-two thousand, five hundred fifty-four".