21297844990 has 16 divisors (see below), whose sum is σ = 40353811920. Its totient is φ = 8070762240.

The previous prime is 21297844949. The next prime is 21297844991. The reversal of 21297844990 is 9944879212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21297844991) 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, 56046771 + ... + 56047150.

It is an arithmetic number, because the mean of its divisors is an integer number (2522113245).

Almost surely, 2^21297844990 is an apocalyptic number.

21297844990 is a deficient number, since it is larger than the sum of its proper divisors (19055966930).

21297844990 is a wasteful number, since it uses less digits than its factorization.

21297844990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112093947.

The product of its (nonzero) digits is 2612736, while the sum is 55.

The spelling of 21297844990 in words is "twenty-one billion, two hundred ninety-seven million, eight hundred forty-four thousand, nine hundred ninety".