20505379 has 2 divisors, whose sum is σ = 20505380. Its totient is φ = 20505378.

The previous prime is 20505361. The next prime is 20505409. The reversal of 20505379 is 97350502.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20505379 - 2¹⁵ = 20472611 is a prime.

It is a super-4 number, since 4×20505379⁴ (a number of 30 digits) contains 4444 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20505379.

It is not a weakly prime, because it can be changed into another prime (20505679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10252689 + 10252690.

It is an arithmetic number, because the mean of its divisors is an integer number (10252690).

Almost surely, 2^20505379 is an apocalyptic number.

20505379 is a deficient number, since it is larger than the sum of its proper divisors (1).

20505379 is an equidigital number, since it uses as much as digits as its factorization.

20505379 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9450, while the sum is 31.

The square root of 20505379 is about 4528.2865412869. The cubic root of 20505379 is about 273.7091190873.

The spelling of 20505379 in words is "twenty million, five hundred five thousand, three hundred seventy-nine".