21379401 has 12 divisors (see below), whose sum is σ = 31182528. Its totient is φ = 14113944.

The previous prime is 21379399. The next prime is 21379441. The reversal of 21379401 is 10497312.

It is not a de Polignac number, because 21379401 - 2¹ = 21379399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21379441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10605 + ... + 12458.

It is an arithmetic number, because the mean of its divisors is an integer number (2598544).

Almost surely, 2^21379401 is an apocalyptic number.

It is an amenable number.

21379401 is a deficient number, since it is larger than the sum of its proper divisors (9803127).

21379401 is a wasteful number, since it uses less digits than its factorization.

21379401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23172 (or 23169 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21379401 is about 4623.7864353796. The cubic root of 21379401 is about 277.5440008144.

The spelling of 21379401 in words is "twenty-one million, three hundred seventy-nine thousand, four hundred one".