121023990 has 64 divisors (see below), whose sum is σ = 326128320. Its totient is φ = 31933440.

The previous prime is 121023983. The next prime is 121023997. The reversal of 121023990 is 99320121.

121023990 = 332² + 333² + ... + 736².

It is an interprime number because it is at equal distance from previous prime (121023983) and next prime (121023997).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121023997) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23880 + ... + 28500.

It is an arithmetic number, because the mean of its divisors is an integer number (5095755).

Almost surely, 2^121023990 is an apocalyptic number.

121023990 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 121023990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163064160).

121023990 is an abundant number, since it is smaller than the sum of its proper divisors (205104330).

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

121023990 is a wasteful number, since it uses less digits than its factorization.

121023990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4734 (or 4728 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 121023990 is about 11001.0904005012. The cubic root of 121023990 is about 494.6414299438.

It can be divided in two parts, 1210 and 23990, that added together give a triangular number (25200 = T₂₂₄).

The spelling of 121023990 in words is "one hundred twenty-one million, twenty-three thousand, nine hundred ninety".