20531154421 has 2 divisors, whose sum is σ = 20531154422. Its totient is φ = 20531154420.

The previous prime is 20531154379. The next prime is 20531154437. The reversal of 20531154421 is 12445113502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20175077521 + 356076900 = 142039^2 + 18870^2 .

It is a cyclic number.

It is not a de Polignac number, because 20531154421 - 2¹⁷ = 20531023349 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20531154421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20531154451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10265577210 + 10265577211.

It is an arithmetic number, because the mean of its divisors is an integer number (10265577211).

Almost surely, 2^20531154421 is an apocalyptic number.

It is an amenable number.

20531154421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20531154421 is an equidigital number, since it uses as much as digits as its factorization.

20531154421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4800, while the sum is 28.

Adding to 20531154421 its reverse (12445113502), we get a palindrome (32976267923).

The spelling of 20531154421 in words is "twenty billion, five hundred thirty-one million, one hundred fifty-four thousand, four hundred twenty-one".