21699253 has 2 divisors, whose sum is σ = 21699254. Its totient is φ = 21699252.

The previous prime is 21699247. The next prime is 21699269. The reversal of 21699253 is 35299612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14607684 + 7091569 = 3822^2 + 2663^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21699253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21699203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10849626 + 10849627.

It is an arithmetic number, because the mean of its divisors is an integer number (10849627).

Almost surely, 2^21699253 is an apocalyptic number.

It is an amenable number.

21699253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21699253 is an equidigital number, since it uses as much as digits as its factorization.

21699253 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29160, while the sum is 37.

The square root of 21699253 is about 4658.2456998316. The cubic root of 21699253 is about 278.9212446272.

It can be divided in two parts, 21699 and 253, that added together give a cube (21952 = 28³).

The spelling of 21699253 in words is "twenty-one million, six hundred ninety-nine thousand, two hundred fifty-three".