20102640 has 40 divisors (see below), whose sum is σ = 62318928. Its totient is φ = 5360640.

The previous prime is 20102609. The next prime is 20102647. The reversal of 20102640 is 4620102.

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

It is a super-2 number, since 2×20102640² = 808232269939200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20102647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41641 + ... + 42120.

Almost surely, 2^20102640 is an apocalyptic number.

20102640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20102640 is an abundant number, since it is smaller than the sum of its proper divisors (42216288).

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

20102640 is a wasteful number, since it uses less digits than its factorization.

20102640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83777 (or 83771 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 20102640 is about 4483.5967704512. The cubic root of 20102640 is about 271.9053159483.

Adding to 20102640 its reverse (4620102), we get a palindrome (24722742).

The spelling of 20102640 in words is "twenty million, one hundred two thousand, six hundred forty".