21242450501 has 2 divisors, whose sum is σ = 21242450502. Its totient is φ = 21242450500.

The previous prime is 21242450477. The next prime is 21242450549. The reversal of 21242450501 is 10505424212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21190624900 + 51825601 = 145570^2 + 7199^2 .

It is a cyclic number.

It is not a de Polignac number, because 21242450501 - 2²² = 21238256197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21242450401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621225250 + 10621225251.

It is an arithmetic number, because the mean of its divisors is an integer number (10621225251).

Almost surely, 2^21242450501 is an apocalyptic number.

It is an amenable number.

21242450501 is a deficient number, since it is larger than the sum of its proper divisors (1).

21242450501 is an equidigital number, since it uses as much as digits as its factorization.

21242450501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3200, while the sum is 26.

Adding to 21242450501 its reverse (10505424212), we get a palindrome (31747874713).

The spelling of 21242450501 in words is "twenty-one billion, two hundred forty-two million, four hundred fifty thousand, five hundred one".