21426377 has 6 divisors (see below), whose sum is σ = 24924618. Its totient is φ = 18365424.

The previous prime is 21426371. The next prime is 21426401. The reversal of 21426377 is 77362412.

It can be written as a sum of positive squares in only one way, i.e., 18412681 + 3013696 = 4291^2 + 1736^2 .

It is not a de Polignac number, because 21426377 - 2¹⁶ = 21360841 is a prime.

It is a super-3 number, since 3×21426377³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21426371) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 218588 + ... + 218685.

It is an arithmetic number, because the mean of its divisors is an integer number (4154103).

Almost surely, 2^21426377 is an apocalyptic number.

It is an amenable number.

21426377 is a deficient number, since it is larger than the sum of its proper divisors (3498241).

21426377 is an equidigital number, since it uses as much as digits as its factorization.

21426377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437287 (or 437280 counting only the distinct ones).

The product of its digits is 14112, while the sum is 32.

The square root of 21426377 is about 4628.8634674183. The cubic root of 21426377 is about 277.7471304440.

Adding to 21426377 its reverse (77362412), we get a palindrome (98788789).

The spelling of 21426377 in words is "twenty-one million, four hundred twenty-six thousand, three hundred seventy-seven".