21279007 has 4 divisors (see below), whose sum is σ = 21338640. Its totient is φ = 21219376.

The previous prime is 21278981. The next prime is 21279029. The reversal of 21279007 is 70097212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21279007 - 2¹⁹ = 20754719 is a prime.

It is a super-2 number, since 2×21279007² = 905592277812098, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21279047) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29278 + ... + 29995.

It is an arithmetic number, because the mean of its divisors is an integer number (5334660).

Almost surely, 2^21279007 is an apocalyptic number.

21279007 is a deficient number, since it is larger than the sum of its proper divisors (59633).

21279007 is an equidigital number, since it uses as much as digits as its factorization.

21279007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59632.

The product of its (nonzero) digits is 1764, while the sum is 28.

The square root of 21279007 is about 4612.9174065877. The cubic root of 21279007 is about 277.1088860198.

The spelling of 21279007 in words is "twenty-one million, two hundred seventy-nine thousand, seven".