20720275 has 6 divisors (see below), whose sum is σ = 25693172. Its totient is φ = 16576200.

The previous prime is 20720261. The next prime is 20720299. The reversal of 20720275 is 57202702.

It is not a de Polignac number, because 20720275 - 2⁹ = 20719763 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25), and also a Moran number because the ratio is a prime number: 828811 = 20720275 / (2 + 0 + 7 + 2 + 0 + 2 + 7 + 5).

It is a Duffinian 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, 414381 + ... + 414430.

Almost surely, 2^20720275 is an apocalyptic number.

20720275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20720275 is a deficient number, since it is larger than the sum of its proper divisors (4972897).

20720275 is an equidigital number, since it uses as much as digits as its factorization.

20720275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 828821 (or 828816 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 25.

The square root of 20720275 is about 4551.9528776120. The cubic root of 20720275 is about 274.6619537699.

Adding to 20720275 its reverse (57202702), we get a palindrome (77922977).

The spelling of 20720275 in words is "twenty million, seven hundred twenty thousand, two hundred seventy-five".