21403432541 has 2 divisors, whose sum is σ = 21403432542. Its totient is φ = 21403432540.

The previous prime is 21403432481. The next prime is 21403432553. The reversal of 21403432541 is 14523430412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16389376441 + 5014056100 = 128021^2 + 70810^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21403432541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21403432241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701716270 + 10701716271.

It is an arithmetic number, because the mean of its divisors is an integer number (10701716271).

Almost surely, 2^21403432541 is an apocalyptic number.

It is an amenable number.

21403432541 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403432541 is an equidigital number, since it uses as much as digits as its factorization.

21403432541 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 29.

Adding to 21403432541 its reverse (14523430412), we get a palindrome (35926862953).

The spelling of 21403432541 in words is "twenty-one billion, four hundred three million, four hundred thirty-two thousand, five hundred forty-one".