102021990 has 32 divisors (see below), whose sum is σ = 279832320. Its totient is φ = 23319264.

The previous prime is 102021989. The next prime is 102021991. The reversal of 102021990 is 99120201.

It is an interprime number because it is at equal distance from previous prime (102021989) and next prime (102021991).

It is a self number, because there is not a number n which added to its sum of digits gives 102021990.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102021991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 242700 + ... + 243119.

It is an arithmetic number, because the mean of its divisors is an integer number (8744760).

Almost surely, 2^102021990 is an apocalyptic number.

102021990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

102021990 is an abundant number, since it is smaller than the sum of its proper divisors (177810330).

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

102021990 is a wasteful number, since it uses less digits than its factorization.

102021990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 485836.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 102021990 is about 10100.5935469159. The cubic root of 102021990 is about 467.2664470597.

The spelling of 102021990 in words is "one hundred two million, twenty-one thousand, nine hundred ninety".