21268787 has 2 divisors, whose sum is σ = 21268788. Its totient is φ = 21268786.

The previous prime is 21268777. The next prime is 21268801. The reversal of 21268787 is 78786212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21268787 - 2¹⁴ = 21252403 is a prime.

It is a super-2 number, since 2×21268787² = 904722600902738, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21268727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10634393 + 10634394.

It is an arithmetic number, because the mean of its divisors is an integer number (10634394).

Almost surely, 2^21268787 is an apocalyptic number.

21268787 is a deficient number, since it is larger than the sum of its proper divisors (1).

21268787 is an equidigital number, since it uses as much as digits as its factorization.

21268787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75264, while the sum is 41.

The square root of 21268787 is about 4611.8095147133. The cubic root of 21268787 is about 277.0645151157.

The spelling of 21268787 in words is "twenty-one million, two hundred sixty-eight thousand, seven hundred eighty-seven".