20002640 has 80 divisors (see below), whose sum is σ = 55496448. Its totient is φ = 6555648.

The previous prime is 20002639. The next prime is 20002651. The reversal of 20002640 is 4620002.

20002640 = T₁₇₉ + T₁₈₀ + ... + T₅₀₀.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (14).

20002640 is a modest number, since divided by 2640 gives 2000 as remainder.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12104 + ... + 13656.

Almost surely, 2^20002640 is an apocalyptic number.

20002640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20002640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27748224).

20002640 is an abundant number, since it is smaller than the sum of its proper divisors (35493808).

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

20002640 is a wasteful number, since it uses less digits than its factorization.

20002640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1596 (or 1590 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 20002640 is about 4472.4311062329. The cubic root of 20002640 is about 271.4537045715.

Adding to 20002640 its reverse (4620002), we get a palindrome (24622642).

The spelling of 20002640 in words is "twenty million, two thousand, six hundred forty".