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21350520881 = 171255912993
BaseRepresentation
bin10011111000100101…
…110001100000110001
32001002221202211121122
4103320211301200301
5322211213132011
613450331432025
71354041301364
oct237045614061
961087684548
1021350520881
1190668a3388
12417a2b5615
132023421111
1410677d80db
1584e5da3db
hex4f8971831

21350520881 has 4 divisors (see below), whose sum is σ = 22606433892. Its totient is φ = 20094607872.

The previous prime is 21350520869. The next prime is 21350520889. The reversal of 21350520881 is 18802505312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19028823025 + 2321697856 = 137945^2 + 48184^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-21350520881 is a prime.

It is a super-2 number, since 2×213505208812 (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 (21350520889) 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, 627956480 + ... + 627956513.

It is an arithmetic number, because the mean of its divisors is an integer number (5651608473).

Almost surely, 221350520881 is an apocalyptic number.

It is an amenable number.

21350520881 is a deficient number, since it is larger than the sum of its proper divisors (1255913011).

21350520881 is a wasteful number, since it uses less digits than its factorization.

21350520881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1255913010.

The product of its (nonzero) digits is 19200, while the sum is 35.

The spelling of 21350520881 in words is "twenty-one billion, three hundred fifty million, five hundred twenty thousand, eight hundred eighty-one".

Divisors: 1 17 1255912993 21350520881