20280497 has 4 divisors (see below), whose sum is σ = 20481396. Its totient is φ = 20079600.

The previous prime is 20280493. The next prime is 20280499. The reversal of 20280497 is 79408202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79408202 = 2 ⋅39704101.

It can be written as a sum of positive squares in 2 ways, for example, as 16982641 + 3297856 = 4121^2 + 1816^2 .

It is a cyclic number.

It is not a de Polignac number, because 20280497 - 2² = 20280493 is a prime.

It is a super-2 number, since 2×20280497² = 822597117134018, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20280493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 100298 + ... + 100499.

It is an arithmetic number, because the mean of its divisors is an integer number (5120349).

Almost surely, 2^20280497 is an apocalyptic number.

It is an amenable number.

20280497 is a deficient number, since it is larger than the sum of its proper divisors (200899).

20280497 is a wasteful number, since it uses less digits than its factorization.

20280497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200898.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 20280497 is about 4503.3872807033. The cubic root of 20280497 is about 272.7048517157.

Adding to 20280497 its reverse (79408202), we get a palindrome (99688699).

The spelling of 20280497 in words is "twenty million, two hundred eighty thousand, four hundred ninety-seven".