21453020529949 has 2 divisors, whose sum is σ = 21453020529950. Its totient is φ = 21453020529948.

The previous prime is 21453020529947. The next prime is 21453020530061. The reversal of 21453020529949 is 94992502035412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20433627407449 + 1019393122500 = 4520357^2 + 1009650^2 .

It is a cyclic number.

It is not a de Polignac number, because 21453020529949 - 2¹ = 21453020529947 is a prime.

Together with 21453020529947, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21453020529949.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21453020529947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10726510264974 + 10726510264975.

It is an arithmetic number, because the mean of its divisors is an integer number (10726510264975).

Almost surely, 2^{21453020529949} is an apocalyptic number.

It is an amenable number.

21453020529949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21453020529949 is an equidigital number, since it uses as much as digits as its factorization.

21453020529949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6998400, while the sum is 55.

The spelling of 21453020529949 in words is "twenty-one trillion, four hundred fifty-three billion, twenty million, five hundred twenty-nine thousand, nine hundred forty-nine".