20515481 has 8 divisors (see below), whose sum is σ = 24825600. Its totient is φ = 16550208.

The previous prime is 20515477. The next prime is 20515483. The reversal of 20515481 is 18451502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20515481 - 2² = 20515477 is a prime.

It is a super-2 number, since 2×20515481² = 841769921322722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20515481.

It is not an unprimeable number, because it can be changed into a prime (20515483) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 86081 + ... + 86318.

It is an arithmetic number, because the mean of its divisors is an integer number (3103200).

Almost surely, 2^20515481 is an apocalyptic number.

It is an amenable number.

20515481 is a deficient number, since it is larger than the sum of its proper divisors (4310119).

20515481 is a wasteful number, since it uses less digits than its factorization.

20515481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172423.

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 20515481 is about 4529.4018368875. The cubic root of 20515481 is about 273.7540594187.

Adding to 20515481 its reverse (18451502), we get a palindrome (38966983).

The spelling of 20515481 in words is "twenty million, five hundred fifteen thousand, four hundred eighty-one".