21742015457 has 4 divisors (see below), whose sum is σ = 22886332080. Its totient is φ = 20597698836.

The previous prime is 21742015417. The next prime is 21742015543. The reversal of 21742015457 is 75451024712.

It is a happy number.

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 21742015457 - 2²⁸ = 21473580001 is a prime.

It is a super-3 number, since 3×21742015457³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21742015457.

It is not an unprimeable number, because it can be changed into a prime (21742015417) 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, 572158283 + ... + 572158320.

It is an arithmetic number, because the mean of its divisors is an integer number (5721583020).

Almost surely, 2^21742015457 is an apocalyptic number.

It is an amenable number.

21742015457 is a deficient number, since it is larger than the sum of its proper divisors (1144316623).

21742015457 is a wasteful number, since it uses less digits than its factorization.

21742015457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1144316622.

The product of its (nonzero) digits is 78400, while the sum is 38.

The spelling of 21742015457 in words is "twenty-one billion, seven hundred forty-two million, fifteen thousand, four hundred fifty-seven".