21451769 has 2 divisors, whose sum is σ = 21451770. Its totient is φ = 21451768.

The previous prime is 21451763. The next prime is 21451789. The reversal of 21451769 is 96715412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20475625 + 976144 = 4525^2 + 988^2 .

It is a cyclic number.

It is not a de Polignac number, because 21451769 - 2⁴ = 21451753 is a prime.

It is a super-2 number, since 2×21451769² = 920356786458722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21451763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10725884 + 10725885.

It is an arithmetic number, because the mean of its divisors is an integer number (10725885).

Almost surely, 2^21451769 is an apocalyptic number.

It is an amenable number.

21451769 is a deficient number, since it is larger than the sum of its proper divisors (1).

21451769 is an equidigital number, since it uses as much as digits as its factorization.

21451769 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15120, while the sum is 35.

The square root of 21451769 is about 4631.6054451993. The cubic root of 21451769 is about 277.8568047801.

The spelling of 21451769 in words is "twenty-one million, four hundred fifty-one thousand, seven hundred sixty-nine".