21475290 has 16 divisors (see below), whose sum is σ = 51540768. Its totient is φ = 5726736.

The previous prime is 21475271. The next prime is 21475297. The reversal of 21475290 is 9257412.

It is a super-2 number, since 2×21475290² = 922376161168200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 715843 = 21475290 / (2 + 1 + 4 + 7 + 5 + 2 + 9 + 0).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21475297) 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, 357892 + ... + 357951.

It is an arithmetic number, because the mean of its divisors is an integer number (3221298).

Almost surely, 2^21475290 is an apocalyptic number.

21475290 is an abundant number, since it is smaller than the sum of its proper divisors (30065478).

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

21475290 is a wasteful number, since it uses less digits than its factorization.

21475290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 715853.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 21475290 is about 4634.1439338890. The cubic root of 21475290 is about 277.9583206152.

The spelling of 21475290 in words is "twenty-one million, four hundred seventy-five thousand, two hundred ninety".