21911901 has 8 divisors (see below), whose sum is σ = 31871904. Its totient is φ = 13279920.

The previous prime is 21911891. The next prime is 21911909. The reversal of 21911901 is 10911912.

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

It is not a de Polignac number, because 21911901 - 2⁶ = 21911837 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21911909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 331966 + ... + 332031.

It is an arithmetic number, because the mean of its divisors is an integer number (3983988).

Almost surely, 2^21911901 is an apocalyptic number.

It is an amenable number.

21911901 is a deficient number, since it is larger than the sum of its proper divisors (9960003).

21911901 is a wasteful number, since it uses less digits than its factorization.

21911901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664011.

The product of its (nonzero) digits is 162, while the sum is 24.

The square root of 21911901 is about 4681.0149540458. The cubic root of 21911901 is about 279.8294071401.

The spelling of 21911901 in words is "twenty-one million, nine hundred eleven thousand, nine hundred one".