21029219749 has 2 divisors, whose sum is σ = 21029219750. Its totient is φ = 21029219748.

The previous prime is 21029219711. The next prime is 21029219753. The reversal of 21029219749 is 94791292012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12333657249 + 8695562500 = 111057^2 + 93250^2 .

It is a cyclic number.

It is not a de Polignac number, because 21029219749 - 2¹¹ = 21029217701 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21029219699 and 21029219708.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21029219149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10514609874 + 10514609875.

It is an arithmetic number, because the mean of its divisors is an integer number (10514609875).

Almost surely, 2^21029219749 is an apocalyptic number.

It is an amenable number.

21029219749 is a deficient number, since it is larger than the sum of its proper divisors (1).

21029219749 is an equidigital number, since it uses as much as digits as its factorization.

21029219749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 163296, while the sum is 46.

The spelling of 21029219749 in words is "twenty-one billion, twenty-nine million, two hundred nineteen thousand, seven hundred forty-nine".