21142510397 has 2 divisors, whose sum is σ = 21142510398. Its totient is φ = 21142510396.

The previous prime is 21142510369. The next prime is 21142510421. The reversal of 21142510397 is 79301524112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15321735961 + 5820774436 = 123781^2 + 76294^2 .

It is a cyclic number.

It is not a de Polignac number, because 21142510397 - 2¹⁰ = 21142509373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21142510307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571255198 + 10571255199.

It is an arithmetic number, because the mean of its divisors is an integer number (10571255199).

Almost surely, 2^21142510397 is an apocalyptic number.

It is an amenable number.

21142510397 is a deficient number, since it is larger than the sum of its proper divisors (1).

21142510397 is an equidigital number, since it uses as much as digits as its factorization.

21142510397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 35.

The spelling of 21142510397 in words is "twenty-one billion, one hundred forty-two million, five hundred ten thousand, three hundred ninety-seven".