15021990 has 128 divisors (see below), whose sum is σ = 43545600. Its totient is φ = 3674880.

The previous prime is 15021961. The next prime is 15021997. The reversal of 15021990 is 9912051.

It is a happy number.

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 (15021997) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 254581 + ... + 254639.

It is an arithmetic number, because the mean of its divisors is an integer number (340200).

Almost surely, 2^15021990 is an apocalyptic number.

15021990 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 15021990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21772800).

15021990 is an abundant number, since it is smaller than the sum of its proper divisors (28523610).

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

15021990 is a wasteful number, since it uses less digits than its factorization.

15021990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 15021990 is about 3875.8212033065. The cubic root of 15021990 is about 246.7416641524.

The spelling of 15021990 in words is "fifteen million, twenty-one thousand, nine hundred ninety".