21401420 has 24 divisors (see below), whose sum is σ = 46494000. Its totient is φ = 8265152.

The previous prime is 21401417. The next prime is 21401437. The reversal of 21401420 is 2410412.

It is a junction number, because it is equal to n+sod(n) for n = 21401395 and 21401404.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17870 + ... + 19029.

It is an arithmetic number, because the mean of its divisors is an integer number (1937250).

Almost surely, 2^21401420 is an apocalyptic number.

21401420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21401420 is an abundant number, since it is smaller than the sum of its proper divisors (25092580).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21401420 is a wasteful number, since it uses less digits than its factorization.

21401420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36937 (or 36935 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21401420 is about 4626.1668798261. The cubic root of 21401420 is about 277.6392505134.

Adding to 21401420 its reverse (2410412), we get a palindrome (23811832).

The spelling of 21401420 in words is "twenty-one million, four hundred one thousand, four hundred twenty".