20515428 has 54 divisors (see below), whose sum is σ = 53675622. Its totient is φ = 6606720.

The previous prime is 20515393. The next prime is 20515463. The reversal of 20515428 is 82451502.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20515393) and next prime (20515463).

It can be written as a sum of positive squares in only one way, i.e., 18301284 + 2214144 = 4278^2 + 1488^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 34300 + ... + 34892.

It is an arithmetic number, because the mean of its divisors is an integer number (993993).

Almost surely, 2^20515428 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20515428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26837811).

20515428 is an abundant number, since it is smaller than the sum of its proper divisors (33160194).

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

20515428 is a wasteful number, since it uses less digits than its factorization.

20515428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 665 (or 629 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 20515428 is about 4529.3959862216. The cubic root of 20515428 is about 273.7538236784.

The spelling of 20515428 in words is "twenty million, five hundred fifteen thousand, four hundred twenty-eight".