21430377 has 6 divisors (see below), whose sum is σ = 30955002. Its totient is φ = 14286912.

The previous prime is 21430369. The next prime is 21430379. The reversal of 21430377 is 77303412.

It can be written as a sum of positive squares in only one way, i.e., 19501056 + 1929321 = 4416^2 + 1389^2 .

It is not a de Polignac number, because 21430377 - 2³ = 21430369 is a prime.

It is a super-2 number, since 2×21430377² = 918522116724258, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21430377.

It is not an unprimeable number, because it can be changed into a prime (21430379) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1190568 + ... + 1190585.

It is an arithmetic number, because the mean of its divisors is an integer number (5159167).

Almost surely, 2^21430377 is an apocalyptic number.

It is an amenable number.

21430377 is a deficient number, since it is larger than the sum of its proper divisors (9524625).

21430377 is a wasteful number, since it uses less digits than its factorization.

21430377 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2381159 (or 2381156 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 27.

The square root of 21430377 is about 4629.2955187588. The cubic root of 21430377 is about 277.7644131822.

Adding to 21430377 its reverse (77303412), we get a palindrome (98733789).

The spelling of 21430377 in words is "twenty-one million, four hundred thirty thousand, three hundred seventy-seven".