21355490 has 32 divisors (see below), whose sum is σ = 42091056. Its totient is φ = 7752960.

The previous prime is 21355483. The next prime is 21355501. The reversal of 21355490 is 9455312.

It can be written as a sum of positive squares in 8 ways, for example, as 625681 + 20729809 = 791^2 + 4553^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6584 + ... + 9276.

Almost surely, 2^21355490 is an apocalyptic number.

21355490 is a deficient number, since it is larger than the sum of its proper divisors (20735566).

21355490 is a wasteful number, since it uses less digits than its factorization.

21355490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2774.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 21355490 is about 4621.2000605903. The cubic root of 21355490 is about 277.4404926103.

The spelling of 21355490 in words is "twenty-one million, three hundred fifty-five thousand, four hundred ninety".