20515401 has 6 divisors (see below), whose sum is σ = 29633370. Its totient is φ = 13676928.

The previous prime is 20515393. The next prime is 20515463. The reversal of 20515401 is 10451502.

It can be written as a sum of positive squares in only one way, i.e., 17842176 + 2673225 = 4224^2 + 1635^2 .

It is not a de Polignac number, because 20515401 - 2³ = 20515393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20514401) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1139736 + ... + 1139753.

It is an arithmetic number, because the mean of its divisors is an integer number (4938895).

Almost surely, 2^20515401 is an apocalyptic number.

It is an amenable number.

20515401 is a deficient number, since it is larger than the sum of its proper divisors (9117969).

20515401 is a wasteful number, since it uses less digits than its factorization.

20515401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2279495 (or 2279492 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 20515401 is about 4529.3930056907. The cubic root of 20515401 is about 273.7537035841.

Adding to 20515401 its reverse (10451502), we get a palindrome (30966903).

The spelling of 20515401 in words is "twenty million, five hundred fifteen thousand, four hundred one".