21075451679 has 2 divisors, whose sum is σ = 21075451680. Its totient is φ = 21075451678.

The previous prime is 21075451591. The next prime is 21075451699. The reversal of 21075451679 is 97615457012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21075451679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21075451699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10537725839 + 10537725840.

It is an arithmetic number, because the mean of its divisors is an integer number (10537725840).

Almost surely, 2^21075451679 is an apocalyptic number.

21075451679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21075451679 is an equidigital number, since it uses as much as digits as its factorization.

21075451679 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 529200, while the sum is 47.

The spelling of 21075451679 in words is "twenty-one billion, seventy-five million, four hundred fifty-one thousand, six hundred seventy-nine".