21510082457 has 4 divisors (see below), whose sum is σ = 22642192080. Its totient is φ = 20377972836.

The previous prime is 21510082453. The next prime is 21510082459. The reversal of 21510082457 is 75428001512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21510082457 - 2² = 21510082453 is a prime.

It is a super-3 number, since 3×21510082457³ (a number of 32 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21510082453) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 566054783 + ... + 566054820.

It is an arithmetic number, because the mean of its divisors is an integer number (5660548020).

Almost surely, 2^21510082457 is an apocalyptic number.

It is an amenable number.

21510082457 is a deficient number, since it is larger than the sum of its proper divisors (1132109623).

21510082457 is a wasteful number, since it uses less digits than its factorization.

21510082457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1132109622.

The product of its (nonzero) digits is 22400, while the sum is 35.

Adding to 21510082457 its reverse (75428001512), we get a palindrome (96938083969).

The spelling of 21510082457 in words is "twenty-one billion, five hundred ten million, eighty-two thousand, four hundred fifty-seven".