20643367 has 4 divisors (see below), whose sum is σ = 21729880. Its totient is φ = 19556856.

The previous prime is 20643353. The next prime is 20643379. The reversal of 20643367 is 76334602.

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 20643367 - 2⁷ = 20643239 is a prime.

It is a super-2 number, since 2×20643367² = 852297202193378, 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 (20643347) 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, 543228 + ... + 543265.

It is an arithmetic number, because the mean of its divisors is an integer number (5432470).

Almost surely, 2^20643367 is an apocalyptic number.

20643367 is a deficient number, since it is larger than the sum of its proper divisors (1086513).

20643367 is a wasteful number, since it uses less digits than its factorization.

20643367 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1086512.

The product of its (nonzero) digits is 18144, while the sum is 31.

The square root of 20643367 is about 4543.4972213043. The cubic root of 20643367 is about 274.3217090788.

Adding to 20643367 its reverse (76334602), we get a palindrome (96977969).

The spelling of 20643367 in words is "twenty million, six hundred forty-three thousand, three hundred sixty-seven".