21401290 has 8 divisors (see below), whose sum is σ = 38522340. Its totient is φ = 8560512.

The previous prime is 21401287. The next prime is 21401291. The reversal of 21401290 is 9210412.

It can be written as a sum of positive squares in 2 ways, for example, as 20403289 + 998001 = 4517^2 + 999^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21401291) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1070055 + ... + 1070074.

Almost surely, 2^21401290 is an apocalyptic number.

21401290 is a deficient number, since it is larger than the sum of its proper divisors (17121050).

21401290 is a wasteful number, since it uses less digits than its factorization.

21401290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2140136.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 21401290 is about 4626.1528292956. The cubic root of 21401290 is about 277.6386883517.

The spelling of 21401290 in words is "twenty-one million, four hundred one thousand, two hundred ninety".