20400203515 has 16 divisors (see below), whose sum is σ = 24713269632. Its totient is φ = 16165338624.

The previous prime is 20400203503. The next prime is 20400203521. The reversal of 20400203515 is 51530200402.

It is a cyclic number.

It is not a de Polignac number, because 20400203515 - 2⁹ = 20400203003 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 280462 + ... + 345628.

It is an arithmetic number, because the mean of its divisors is an integer number (1544579352).

Almost surely, 2^20400203515 is an apocalyptic number.

20400203515 is a deficient number, since it is larger than the sum of its proper divisors (4313066117).

20400203515 is a wasteful number, since it uses less digits than its factorization.

20400203515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65766.

The product of its (nonzero) digits is 1200, while the sum is 22.

Adding to 20400203515 its reverse (51530200402), we get a palindrome (71930403917).

The spelling of 20400203515 in words is "twenty billion, four hundred million, two hundred three thousand, five hundred fifteen".