21277421 has 8 divisors (see below), whose sum is σ = 24577344. Its totient is φ = 18205120.

The previous prime is 21277411. The next prime is 21277423. The reversal of 21277421 is 12477212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21277421 - 2¹⁸ = 21015277 is a prime.

It is a super-2 number, since 2×21277421² = 905457288822482, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21277423) 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 in 7 ways as a sum of consecutive naturals, for example, 56705 + ... + 57078.

It is an arithmetic number, because the mean of its divisors is an integer number (3072168).

Almost surely, 2^21277421 is an apocalyptic number.

It is an amenable number.

21277421 is a deficient number, since it is larger than the sum of its proper divisors (3299923).

21277421 is a wasteful number, since it uses less digits than its factorization.

21277421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113811.

The product of its digits is 1568, while the sum is 26.

The square root of 21277421 is about 4612.7454948219. The cubic root of 21277421 is about 277.1020012121.

The spelling of 21277421 in words is "twenty-one million, two hundred seventy-seven thousand, four hundred twenty-one".