191223990 has 112 divisors (see below), whose sum is σ = 546779808. Its totient is φ = 47962368.

The previous prime is 191223971. The next prime is 191224009. The reversal of 191223990 is 99322191.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (191223971) and next prime (191224009).

It is a super-2 number, since 2×191223990² = 73133228703040200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 123159 + ... + 124701.

Almost surely, 2^191223990 is an apocalyptic number.

191223990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 191223990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (273389904).

191223990 is an abundant number, since it is smaller than the sum of its proper divisors (355555818).

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

191223990 is a wasteful number, since it uses less digits than its factorization.

191223990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1585 (or 1570 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 191223990 is about 13828.3762604291. The cubic root of 191223990 is about 576.1215563767.

The spelling of 191223990 in words is "one hundred ninety-one million, two hundred twenty-three thousand, nine hundred ninety".