21394901 has 4 divisors (see below), whose sum is σ = 23339904. Its totient is φ = 19449900.

The previous prime is 21394897. The next prime is 21394903. The reversal of 21394901 is 10949312.

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 21394901 - 2² = 21394897 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21394903) 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, 972485 + ... + 972506.

It is an arithmetic number, because the mean of its divisors is an integer number (5834976).

Almost surely, 2^21394901 is an apocalyptic number.

It is an amenable number.

21394901 is a deficient number, since it is larger than the sum of its proper divisors (1945003).

21394901 is a wasteful number, since it uses less digits than its factorization.

21394901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1945002.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 21394901 is about 4625.4622471705. The cubic root of 21394901 is about 277.6110574608.

The spelling of 21394901 in words is "twenty-one million, three hundred ninety-four thousand, nine hundred one".