21040011551 has 8 divisors (see below), whose sum is σ = 23851025520. Its totient is φ = 18399362112.

The previous prime is 21040011547. The next prime is 21040011617. The reversal of 21040011551 is 15511004012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21040011551 - 2² = 21040011547 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040011511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42590870 + ... + 42591363.

It is an arithmetic number, because the mean of its divisors is an integer number (2981378190).

Almost surely, 2^21040011551 is an apocalyptic number.

21040011551 is a deficient number, since it is larger than the sum of its proper divisors (2811013969).

21040011551 is a wasteful number, since it uses less digits than its factorization.

21040011551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85182265.

The product of its (nonzero) digits is 200, while the sum is 20.

Adding to 21040011551 its reverse (15511004012), we get a palindrome (36551015563).

The spelling of 21040011551 in words is "twenty-one billion, forty million, eleven thousand, five hundred fifty-one".