20021220431 has 2 divisors, whose sum is σ = 20021220432. Its totient is φ = 20021220430.

The previous prime is 20021220407. The next prime is 20021220449. The reversal of 20021220431 is 13402212002.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20021220431 is a prime.

It is a super-2 number, since 2×20021220431² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20024220431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10010610215 + 10010610216.

It is an arithmetic number, because the mean of its divisors is an integer number (10010610216).

Almost surely, 2^20021220431 is an apocalyptic number.

20021220431 is a deficient number, since it is larger than the sum of its proper divisors (1).

20021220431 is an equidigital number, since it uses as much as digits as its factorization.

20021220431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 20021220431 its reverse (13402212002), we get a palindrome (33423432433).

The spelling of 20021220431 in words is "twenty billion, twenty-one million, two hundred twenty thousand, four hundred thirty-one".