21874261 has 2 divisors, whose sum is σ = 21874262. Its totient is φ = 21874260.

The previous prime is 21874241. The next prime is 21874267. The reversal of 21874261 is 16247812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15062161 + 6812100 = 3881^2 + 2610^2 .

It is a cyclic number.

It is not a de Polignac number, because 21874261 - 2¹³ = 21866069 is a prime.

It is a super-2 number, since 2×21874261² = 956966588592242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21874267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10937130 + 10937131.

It is an arithmetic number, because the mean of its divisors is an integer number (10937131).

Almost surely, 2^21874261 is an apocalyptic number.

It is an amenable number.

21874261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21874261 is an equidigital number, since it uses as much as digits as its factorization.

21874261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5376, while the sum is 31.

The square root of 21874261 is about 4676.9927303771. The cubic root of 21874261 is about 279.6690861092.

The spelling of 21874261 in words is "twenty-one million, eight hundred seventy-four thousand, two hundred sixty-one".