21279069 has 48 divisors (see below), whose sum is σ = 38313600. Its totient is φ = 11104128.

The previous prime is 21279061. The next prime is 21279077. The reversal of 21279069 is 96097212.

It is an interprime number because it is at equal distance from previous prime (21279061) and next prime (21279077).

It is not a de Polignac number, because 21279069 - 2³ = 21279061 is a prime.

It is a super-2 number, since 2×21279069² = 905597555013522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21279061) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 34407 + ... + 35019.

It is an arithmetic number, because the mean of its divisors is an integer number (798200).

Almost surely, 2^21279069 is an apocalyptic number.

21279069 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21279069 is a deficient number, since it is larger than the sum of its proper divisors (17034531).

21279069 is a wasteful number, since it uses less digits than its factorization.

21279069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 674 (or 671 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 21279069 is about 4612.9241268419. The cubic root of 21279069 is about 277.1091551541.

The spelling of 21279069 in words is "twenty-one million, two hundred seventy-nine thousand, sixty-nine".