21503410064 has 40 divisors (see below), whose sum is σ = 42010349112. Its totient is φ = 10662348800.

The previous prime is 21503410057. The next prime is 21503410081. The reversal of 21503410064 is 46001430512.

It can be written as a sum of positive squares in 4 ways, for example, as 12476890000 + 9026520064 = 111700^2 + 95008^2 .

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, 1100282 + ... + 1119654.

Almost surely, 2^21503410064 is an apocalyptic number.

It is an amenable number.

21503410064 is a deficient number, since it is larger than the sum of its proper divisors (20506939048).

21503410064 is a wasteful number, since it uses less digits than its factorization.

21503410064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19955 (or 19949 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

Adding to 21503410064 its reverse (46001430512), we get a palindrome (67504840576).

The spelling of 21503410064 in words is "twenty-one billion, five hundred three million, four hundred ten thousand, sixty-four".