21919401 has 24 divisors (see below), whose sum is σ = 36516480. Its totient is φ = 12410496.

The previous prime is 21919399. The next prime is 21919411. The reversal of 21919401 is 10491912.

It is not a de Polignac number, because 21919401 - 2¹ = 21919399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21919411) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5580 + ... + 8658.

It is an arithmetic number, because the mean of its divisors is an integer number (1521520).

Almost surely, 2^21919401 is an apocalyptic number.

21919401 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21919401 is a deficient number, since it is larger than the sum of its proper divisors (14597079).

21919401 is a wasteful number, since it uses less digits than its factorization.

21919401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3205 (or 3202 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 21919401 is about 4681.8159938212. The cubic root of 21919401 is about 279.8613301447.

The spelling of 21919401 in words is "twenty-one million, nine hundred nineteen thousand, four hundred one".