20211643553 has 16 divisors (see below), whose sum is σ = 22365092736. Its totient is φ = 18167888640.

The previous prime is 20211643549. The next prime is 20211643561. The reversal of 20211643553 is 35534611202.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20211643553 - 2² = 20211643549 is a prime.

It is a super-2 number, since 2×20211643553² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20211643513) 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, 219350 + ... + 297552.

It is an arithmetic number, because the mean of its divisors is an integer number (1397818296).

Almost surely, 2^20211643553 is an apocalyptic number.

20211643553 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

20211643553 is a deficient number, since it is larger than the sum of its proper divisors (2153449183).

20211643553 is a wasteful number, since it uses less digits than its factorization.

20211643553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78904.

The product of its (nonzero) digits is 21600, while the sum is 32.

The spelling of 20211643553 in words is "twenty billion, two hundred eleven million, six hundred forty-three thousand, five hundred fifty-three".