21006620494 has 16 divisors (see below), whose sum is σ = 32362616880. Its totient is φ = 10220898240.

The previous prime is 21006620491. The next prime is 21006620497. The reversal of 21006620494 is 49402660012.

It is an interprime number because it is at equal distance from previous prime (21006620491) and next prime (21006620497).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21006620491) 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, 430887 + ... + 477154.

It is an arithmetic number, because the mean of its divisors is an integer number (2022663555).

Almost surely, 2^21006620494 is an apocalyptic number.

21006620494 is a deficient number, since it is larger than the sum of its proper divisors (11355996386).

21006620494 is a wasteful number, since it uses less digits than its factorization.

21006620494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908355.

The product of its (nonzero) digits is 20736, while the sum is 34.

The spelling of 21006620494 in words is "twenty-one billion, six million, six hundred twenty thousand, four hundred ninety-four".