21221000004043 has 16 divisors (see below), whose sum is σ = 24817821405696. Its totient is φ = 17765533255680.

The previous prime is 21221000003989. The next prime is 21221000004053. The reversal of 21221000004043 is 34040000012212.

It is a de Polignac number, because none of the positive numbers 2^k-21221000004043 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21221000004043.

It is not an unprimeable number, because it can be changed into a prime (21221000004053) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4328523 + ... + 7821643.

It is an arithmetic number, because the mean of its divisors is an integer number (1551113837856).

Almost surely, 2^{21221000004043} is an apocalyptic number.

21221000004043 is a deficient number, since it is larger than the sum of its proper divisors (3596821401653).

21221000004043 is a wasteful number, since it uses less digits than its factorization.

21221000004043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3513354.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21221000004043 its reverse (34040000012212), we get a palindrome (55261000016255).

The spelling of 21221000004043 in words is "twenty-one trillion, two hundred twenty-one billion, four thousand, forty-three".