21069775 has 6 divisors (see below), whose sum is σ = 26126552. Its totient is φ = 16855800.

The previous prime is 21069757. The next prime is 21069781. The reversal of 21069775 is 57796012.

It is not a de Polignac number, because 21069775 - 2¹⁹ = 20545487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 421371 + ... + 421420.

Almost surely, 2^21069775 is an apocalyptic number.

21069775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21069775 is a deficient number, since it is larger than the sum of its proper divisors (5056777).

21069775 is an equidigital number, since it uses as much as digits as its factorization.

21069775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 842801 (or 842796 counting only the distinct ones).

The product of its (nonzero) digits is 26460, while the sum is 37.

The square root of 21069775 is about 4590.1824582472. The cubic root of 21069775 is about 276.1976416403.

It can be divided in two parts, 2106 and 9775, that added together give a square (11881 = 109²).

The spelling of 21069775 in words is "twenty-one million, sixty-nine thousand, seven hundred seventy-five".