21420601 has 4 divisors (see below), whose sum is σ = 21628672. Its totient is φ = 21212532.

The previous prime is 21420587. The next prime is 21420643. The reversal of 21420601 is 10602412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21420601 - 2⁵ = 21420569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21420661) 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 3 ways as a sum of consecutive naturals, for example, 103881 + ... + 104086.

It is an arithmetic number, because the mean of its divisors is an integer number (5407168).

Almost surely, 2^21420601 is an apocalyptic number.

It is an amenable number.

21420601 is a deficient number, since it is larger than the sum of its proper divisors (208071).

21420601 is a wasteful number, since it uses less digits than its factorization.

21420601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208070.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21420601 is about 4628.2395141133. The cubic root of 21420601 is about 277.7221703741.

The spelling of 21420601 in words is "twenty-one million, four hundred twenty thousand, six hundred one".