20640534 has 8 divisors (see below), whose sum is σ = 41281080. Its totient is φ = 6880176.

The previous prime is 20640511. The next prime is 20640541. The reversal of 20640534 is 43504602.

It is a sphenic number, since it is the product of 3 distinct primes.

20640534 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1720039 + ... + 1720050.

It is an arithmetic number, because the mean of its divisors is an integer number (5160135).

Almost surely, 2^20640534 is an apocalyptic number.

20640534 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20640534 is a wasteful number, since it uses less digits than its factorization.

20640534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3440094.

The product of its (nonzero) digits is 2880, while the sum is 24.

The square root of 20640534 is about 4543.1854463581. The cubic root of 20640534 is about 274.3091596247.

The spelling of 20640534 in words is "twenty million, six hundred forty thousand, five hundred thirty-four".