21234670643 has 2 divisors, whose sum is σ = 21234670644. Its totient is φ = 21234670642.

The previous prime is 21234670631. The next prime is 21234670651. The reversal of 21234670643 is 34607643212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21234670643 - 2¹⁶ = 21234605107 is a prime.

It is a super-2 number, since 2×21234670643² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21234670597 and 21234670606.

It is not a weakly prime, because it can be changed into another prime (21234670243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617335321 + 10617335322.

It is an arithmetic number, because the mean of its divisors is an integer number (10617335322).

Almost surely, 2^21234670643 is an apocalyptic number.

21234670643 is a deficient number, since it is larger than the sum of its proper divisors (1).

21234670643 is an equidigital number, since it uses as much as digits as its factorization.

21234670643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 38.

The spelling of 21234670643 in words is "twenty-one billion, two hundred thirty-four million, six hundred seventy thousand, six hundred forty-three".