1661290 has 32 divisors (see below), whose sum is σ = 3234816. Its totient is φ = 612480.

The previous prime is 1661281. The next prime is 1661293. The reversal of 1661290 is 921661.

It is not an unprimeable number, because it can be changed into a prime (1661293) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7014 + ... + 7246.

It is an arithmetic number, because the mean of its divisors is an integer number (101088).

2^1661290 is an apocalyptic number.

1661290 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1661290 is a deficient number, since it is larger than the sum of its proper divisors (1573526).

1661290 is a wasteful number, since it uses less digits than its factorization.

1661290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 1661290 is about 1288.9103925409. The cubic root of 1661290 is about 118.4354779395.

The spelling of 1661290 in words is "one million, six hundred sixty-one thousand, two hundred ninety".