21450761517 has 16 divisors (see below), whose sum is σ = 30987696960. Its totient is φ = 13146292992.

The previous prime is 21450761509. The next prime is 21450761543. The reversal of 21450761517 is 71516705412.

It is not a de Polignac number, because 21450761517 - 2³ = 21450761509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21450761567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4888542 + ... + 4892927.

It is an arithmetic number, because the mean of its divisors is an integer number (1936731060).

Almost surely, 2^21450761517 is an apocalyptic number.

It is an amenable number.

21450761517 is a deficient number, since it is larger than the sum of its proper divisors (9536935443).

21450761517 is a wasteful number, since it uses less digits than its factorization.

21450761517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9781532.

The product of its (nonzero) digits is 58800, while the sum is 39.

The spelling of 21450761517 in words is "twenty-one billion, four hundred fifty million, seven hundred sixty-one thousand, five hundred seventeen".