20402556 has 24 divisors (see below), whose sum is σ = 47733840. Its totient is φ = 6782592.

The previous prime is 20402537. The next prime is 20402563. The reversal of 20402556 is 65520402.

It is a congruent number.

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, 2830 + ... + 6986.

It is an arithmetic number, because the mean of its divisors is an integer number (1988910).

Almost surely, 2^20402556 is an apocalyptic number.

It is an amenable number.

20402556 is an abundant number, since it is smaller than the sum of its proper divisors (27331284).

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

20402556 is a wasteful number, since it uses less digits than its factorization.

20402556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4573 (or 4571 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 20402556 is about 4516.9188613479. The cubic root of 20402556 is about 273.2508528978.

Adding to 20402556 its reverse (65520402), we get a palindrome (85922958).

The spelling of 20402556 in words is "twenty million, four hundred two thousand, five hundred fifty-six".