20846640 has 40 divisors (see below), whose sum is σ = 64625328. Its totient is φ = 5559040.

The previous prime is 20846627. The next prime is 20846653. The reversal of 20846640 is 4664802.

It is an interprime number because it is at equal distance from previous prime (20846627) and next prime (20846653).

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20846598 and 20846607.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43191 + ... + 43670.

Almost surely, 2^20846640 is an apocalyptic number.

20846640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20846640 is an abundant number, since it is smaller than the sum of its proper divisors (43778688).

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

20846640 is a wasteful number, since it uses less digits than its factorization.

20846640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86877 (or 86871 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 20846640 is about 4565.8120854893. The cubic root of 20846640 is about 275.2191751332.

The spelling of 20846640 in words is "twenty million, eight hundred forty-six thousand, six hundred forty".