21235474397 has 2 divisors, whose sum is σ = 21235474398. Its totient is φ = 21235474396.

The previous prime is 21235474327. The next prime is 21235474453. The reversal of 21235474397 is 79347453212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18809025316 + 2426449081 = 137146^2 + 49259^2 .

It is a cyclic number.

It is not a de Polignac number, because 21235474397 - 2¹⁶ = 21235408861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21235474327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617737198 + 10617737199.

It is an arithmetic number, because the mean of its divisors is an integer number (10617737199).

Almost surely, 2^21235474397 is an apocalyptic number.

It is an amenable number.

21235474397 is a deficient number, since it is larger than the sum of its proper divisors (1).

21235474397 is an equidigital number, since it uses as much as digits as its factorization.

21235474397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1270080, while the sum is 47.

The spelling of 21235474397 in words is "twenty-one billion, two hundred thirty-five million, four hundred seventy-four thousand, three hundred ninety-seven".