21420415 has 8 divisors (see below), whose sum is σ = 26591040. Its totient is φ = 16545312.

The previous prime is 21420403. The next prime is 21420433. The reversal of 21420415 is 51402412.

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

It is not a de Polignac number, because 21420415 - 2⁹ = 21419903 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21420392 and 21420401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73719 + ... + 74008.

It is an arithmetic number, because the mean of its divisors is an integer number (3323880).

Almost surely, 2^21420415 is an apocalyptic number.

21420415 is a deficient number, since it is larger than the sum of its proper divisors (5170625).

21420415 is a wasteful number, since it uses less digits than its factorization.

21420415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147761.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21420415 is about 4628.2194200362. The cubic root of 21420415 is about 277.7213665299.

Adding to 21420415 its reverse (51402412), we get a palindrome (72822827).

The spelling of 21420415 in words is "twenty-one million, four hundred twenty thousand, four hundred fifteen".