21401983 has 16 divisors (see below), whose sum is σ = 23115456. Its totient is φ = 19768320.

The previous prime is 21401957. The next prime is 21401987. The reversal of 21401983 is 38910412.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21401983 - 2⁵ = 21401951 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 (21401987) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 118153 + ... + 118333.

It is an arithmetic number, because the mean of its divisors is an integer number (1444716).

Almost surely, 2^21401983 is an apocalyptic number.

21401983 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21401983 is a deficient number, since it is larger than the sum of its proper divisors (1713473).

21401983 is a wasteful number, since it uses less digits than its factorization.

21401983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 21401983 is about 4626.2277289386. The cubic root of 21401983 is about 277.6416850797.

The spelling of 21401983 in words is "twenty-one million, four hundred one thousand, nine hundred eighty-three".