21144155401 has 2 divisors, whose sum is σ = 21144155402. Its totient is φ = 21144155400.

The previous prime is 21144155327. The next prime is 21144155411. The reversal of 21144155401 is 10455144112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13262977225 + 7881178176 = 115165^2 + 88776^2 .

It is a cyclic number.

It is not a de Polignac number, because 21144155401 - 2⁷ = 21144155273 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21144155401.

It is not a weakly prime, because it can be changed into another prime (21144155411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572077700 + 10572077701.

It is an arithmetic number, because the mean of its divisors is an integer number (10572077701).

Almost surely, 2^21144155401 is an apocalyptic number.

It is an amenable number.

21144155401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21144155401 is an equidigital number, since it uses as much as digits as its factorization.

21144155401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3200, while the sum is 28.

Adding to 21144155401 its reverse (10455144112), we get a palindrome (31599299513).

The spelling of 21144155401 in words is "twenty-one billion, one hundred forty-four million, one hundred fifty-five thousand, four hundred one".