21231430990 has 96 divisors (see below), whose sum is σ = 50170168800. Its totient is φ = 6389349120.

The previous prime is 21231430981. The next prime is 21231430999. The reversal of 21231430990 is 9903413212.

It is an interprime number because it is at equal distance from previous prime (21231430981) and next prime (21231430999).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231430999) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 88396 + ... + 224224.

It is an arithmetic number, because the mean of its divisors is an integer number (522605925).

Almost surely, 2^21231430990 is an apocalyptic number.

21231430990 is an abundant number, since it is smaller than the sum of its proper divisors (28938737810).

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

21231430990 is a wasteful number, since it uses less digits than its factorization.

21231430990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135890 (or 135883 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 34.

The spelling of 21231430990 in words is "twenty-one billion, two hundred thirty-one million, four hundred thirty thousand, nine hundred ninety".