21379045 has 4 divisors (see below), whose sum is σ = 25654860. Its totient is φ = 17103232.

The previous prime is 21379027. The next prime is 21379049. The reversal of 21379045 is 54097312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3392964 + 17986081 = 1842^2 + 4241^2 .

It is a cyclic number.

It is not a de Polignac number, because 21379045 - 2²³ = 12990437 is a prime.

It is a super-2 number, since 2×21379045² = 914127130224050, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21378998 and 21379016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21379049) 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, 2137900 + ... + 2137909.

It is an arithmetic number, because the mean of its divisors is an integer number (6413715).

Almost surely, 2^21379045 is an apocalyptic number.

It is an amenable number.

21379045 is a deficient number, since it is larger than the sum of its proper divisors (4275815).

21379045 is an equidigital number, since it uses as much as digits as its factorization.

21379045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4275814.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 21379045 is about 4623.7479386316. The cubic root of 21379045 is about 277.5424602939.

The spelling of 21379045 in words is "twenty-one million, three hundred seventy-nine thousand, forty-five".