1221770 has 32 divisors (see below), whose sum is σ = 2488320. Its totient is φ = 427840.

The previous prime is 1221767. The next prime is 1221791. The reversal of 1221770 is 771221.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2999 + ... + 3381.

It is an arithmetic number, because the mean of its divisors is an integer number (77760).

2^1221770 is an apocalyptic number.

1221770 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221770 is an abundant number, since it is smaller than the sum of its proper divisors (1266550).

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

1221770 is a wasteful number, since it uses less digits than its factorization.

1221770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430.

The product of its (nonzero) digits is 196, while the sum is 20.

The square root of 1221770 is about 1105.3370526676. The cubic root of 1221770 is about 106.9046228432.

Adding to 1221770 its reverse (771221), we get a palindrome (1992991).

It can be divided in two parts, 1221 and 770, that added together give a palindrome (1991).

The spelling of 1221770 in words is "one million, two hundred twenty-one thousand, seven hundred seventy".