21553349757 has 16 divisors (see below), whose sum is σ = 29761492992. Its totient is φ = 13860074160.

The previous prime is 21553349731. The next prime is 21553349759. The reversal of 21553349757 is 75794335512.

It is a happy number.

It is not a de Polignac number, because 21553349757 - 2⁶ = 21553349693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21553349759) 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, 348903 + ... + 406004.

It is an arithmetic number, because the mean of its divisors is an integer number (1860093312).

Almost surely, 2^21553349757 is an apocalyptic number.

It is an amenable number.

21553349757 is a deficient number, since it is larger than the sum of its proper divisors (8208143235).

21553349757 is a wasteful number, since it uses less digits than its factorization.

21553349757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 755248.

The product of its digits is 3969000, while the sum is 51.

The spelling of 21553349757 in words is "twenty-one billion, five hundred fifty-three million, three hundred forty-nine thousand, seven hundred fifty-seven".