21079437947 has 2 divisors, whose sum is σ = 21079437948. Its totient is φ = 21079437946.

The previous prime is 21079437853. The next prime is 21079437949. The reversal of 21079437947 is 74973497012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21079437947 is a prime.

It is a super-2 number, since 2×21079437947² (a number of 21 digits) contains 22 as substring.

Together with 21079437949, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21079437949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10539718973 + 10539718974.

It is an arithmetic number, because the mean of its divisors is an integer number (10539718974).

Almost surely, 2^21079437947 is an apocalyptic number.

21079437947 is a deficient number, since it is larger than the sum of its proper divisors (1).

21079437947 is an equidigital number, since it uses as much as digits as its factorization.

21079437947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2667168, while the sum is 53.

The spelling of 21079437947 in words is "twenty-one billion, seventy-nine million, four hundred thirty-seven thousand, nine hundred forty-seven".