21211220001 has 16 divisors (see below), whose sum is σ = 28440746048. Its totient is φ = 14061427200.

The previous prime is 21211219973. The next prime is 21211220021. The reversal of 21211220001 is 10002211212.

It is not a de Polignac number, because 21211220001 - 2⁹ = 21211219489 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21211220021) 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, 478365 + ... + 520821.

It is an arithmetic number, because the mean of its divisors is an integer number (1777546628).

Almost surely, 2^21211220001 is an apocalyptic number.

It is an amenable number.

21211220001 is a deficient number, since it is larger than the sum of its proper divisors (7229526047).

21211220001 is a wasteful number, since it uses less digits than its factorization.

21211220001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43392.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21211220001 its reverse (10002211212), we get a palindrome (31213431213).

The spelling of 21211220001 in words is "twenty-one billion, two hundred eleven million, two hundred twenty thousand, one".