21947080 has 16 divisors (see below), whose sum is σ = 49381020. Its totient is φ = 8778816.

The previous prime is 21947077. The next prime is 21947089. The reversal of 21947080 is 8074912.

It can be written as a sum of positive squares in 2 ways, for example, as 18714276 + 3232804 = 4326^2 + 1798^2 .

It is not an unprimeable number, because it can be changed into a prime (21947089) 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, 274299 + ... + 274378.

Almost surely, 2^21947080 is an apocalyptic number.

21947080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21947080 is an abundant number, since it is smaller than the sum of its proper divisors (27433940).

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

21947080 is a wasteful number, since it uses less digits than its factorization.

21947080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548688 (or 548684 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21947080 is about 4684.7710723151. The cubic root of 21947080 is about 279.9790800697.

The spelling of 21947080 in words is "twenty-one million, nine hundred forty-seven thousand, eighty".