21099920291990 has 8 divisors (see below), whose sum is σ = 37979856525600. Its totient is φ = 8439968116792.

The previous prime is 21099920291893. The next prime is 21099920292013. The reversal of 21099920291990 is 9919202999012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1054996014590 + ... + 1054996014609.

It is an arithmetic number, because the mean of its divisors is an integer number (4747482065700).

Almost surely, 2^{21099920291990} is an apocalyptic number.

21099920291990 is a deficient number, since it is larger than the sum of its proper divisors (16879936233610).

21099920291990 is a wasteful number, since it uses less digits than its factorization.

21099920291990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2109992029206.

The product of its (nonzero) digits is 4251528, while the sum is 62.

The spelling of 21099920291990 in words is "twenty-one trillion, ninety-nine billion, nine hundred twenty million, two hundred ninety-one thousand, nine hundred ninety".