21425377 has 2 divisors, whose sum is σ = 21425378. Its totient is φ = 21425376.

The previous prime is 21425363. The next prime is 21425387. The reversal of 21425377 is 77352412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21150801 + 274576 = 4599^2 + 524^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21425377 is a prime.

It is not a weakly prime, because it can be changed into another prime (21425317) 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, 10712688 + 10712689.

It is an arithmetic number, because the mean of its divisors is an integer number (10712689).

Almost surely, 2^21425377 is an apocalyptic number.

It is an amenable number.

21425377 is a deficient number, since it is larger than the sum of its proper divisors (1).

21425377 is an equidigital number, since it uses as much as digits as its factorization.

21425377 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11760, while the sum is 31.

The square root of 21425377 is about 4628.7554482820. The cubic root of 21425377 is about 277.7428094233.

Adding to 21425377 its reverse (77352412), we get a palindrome (98777789).

The spelling of 21425377 in words is "twenty-one million, four hundred twenty-five thousand, three hundred seventy-seven".