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21764261 is a prime number
BaseRepresentation
bin101001100000…
…1100010100101
31111221201221202
41103001202211
521032424021
62054252245
7352664441
oct123014245
944851852
1021764261
11113158a2
127357085
13468047c
142c67821
151d9da0b
hex14c18a5

21764261 has 2 divisors, whose sum is σ = 21764262. Its totient is φ = 21764260.

The previous prime is 21764257. The next prime is 21764273. The reversal of 21764261 is 16246712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15484225 + 6280036 = 3935^2 + 2506^2 .

It is a cyclic number.

It is not a de Polignac number, because 21764261 - 22 = 21764257 is a prime.

It is a super-2 number, since 2×217642612 = 947366113752242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21764221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10882130 + 10882131.

It is an arithmetic number, because the mean of its divisors is an integer number (10882131).

Almost surely, 221764261 is an apocalyptic number.

It is an amenable number.

21764261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21764261 is an equidigital number, since it uses as much as digits as its factorization.

21764261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 29.

The square root of 21764261 is about 4665.2182156894. The cubic root of 21764261 is about 279.1995035951.

The spelling of 21764261 in words is "twenty-one million, seven hundred sixty-four thousand, two hundred sixty-one".