21055301551 has 2 divisors, whose sum is σ = 21055301552. Its totient is φ = 21055301550.

The previous prime is 21055301543. The next prime is 21055301591. The reversal of 21055301551 is 15510355012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21055301551 - 2³ = 21055301543 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21055301521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10527650775 + 10527650776.

It is an arithmetic number, because the mean of its divisors is an integer number (10527650776).

Almost surely, 2^21055301551 is an apocalyptic number.

21055301551 is a deficient number, since it is larger than the sum of its proper divisors (1).

21055301551 is an equidigital number, since it uses as much as digits as its factorization.

21055301551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3750, while the sum is 28.

Adding to 21055301551 its reverse (15510355012), we get a palindrome (36565656563).

The spelling of 21055301551 in words is "twenty-one billion, fifty-five million, three hundred one thousand, five hundred fifty-one".