21371801 has 4 divisors (see below), whose sum is σ = 23314704. Its totient is φ = 19428900.

The previous prime is 21371797. The next prime is 21371809. The reversal of 21371801 is 10817312.

It is a happy number.

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 21371801 - 2² = 21371797 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21371809) 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, 971435 + ... + 971456.

It is an arithmetic number, because the mean of its divisors is an integer number (5828676).

Almost surely, 2^21371801 is an apocalyptic number.

It is an amenable number.

21371801 is a deficient number, since it is larger than the sum of its proper divisors (1942903).

21371801 is a wasteful number, since it uses less digits than its factorization.

21371801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1942902.

The product of its (nonzero) digits is 336, while the sum is 23.

The square root of 21371801 is about 4622.9645250640. The cubic root of 21371801 is about 277.5111095842.

The spelling of 21371801 in words is "twenty-one million, three hundred seventy-one thousand, eight hundred one".