21415601 has 4 divisors (see below), whose sum is σ = 22154100. Its totient is φ = 20677104.

The previous prime is 21415561. The next prime is 21415607. The reversal of 21415601 is 10651412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12082576 + 9333025 = 3476^2 + 3055^2 .

It is a cyclic number.

It is not a de Polignac number, because 21415601 - 2²² = 17221297 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21415607) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 369206 + ... + 369263.

It is an arithmetic number, because the mean of its divisors is an integer number (5538525).

Almost surely, 2^21415601 is an apocalyptic number.

It is an amenable number.

21415601 is a deficient number, since it is larger than the sum of its proper divisors (738499).

21415601 is an equidigital number, since it uses as much as digits as its factorization.

21415601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 738498.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21415601 is about 4627.6993203967. The cubic root of 21415601 is about 277.7005600419.

The spelling of 21415601 in words is "twenty-one million, four hundred fifteen thousand, six hundred one".