21402377 has 8 divisors (see below), whose sum is σ = 22205640. Its totient is φ = 20603520.

The previous prime is 21402373. The next prime is 21402383. The reversal of 21402377 is 77320412.

It can be written as a sum of positive squares in 4 ways, for example, as 1430416 + 19971961 = 1196^2 + 4469^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21402377 - 2² = 21402373 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21402373) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11333 + ... + 13085.

It is an arithmetic number, because the mean of its divisors is an integer number (2775705).

Almost surely, 2^21402377 is an apocalyptic number.

It is an amenable number.

21402377 is a deficient number, since it is larger than the sum of its proper divisors (803263).

21402377 is a wasteful number, since it uses less digits than its factorization.

21402377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2203.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 21402377 is about 4626.2703120332. The cubic root of 21402377 is about 277.6433888183.

Adding to 21402377 its reverse (77320412), we get a palindrome (98722789).

The spelling of 21402377 in words is "twenty-one million, four hundred two thousand, three hundred seventy-seven".