1981570 has 16 divisors (see below), whose sum is σ = 3690360. Its totient is φ = 765184.

The previous prime is 1981547. The next prime is 1981583. The reversal of 1981570 is 751891.

It can be written as a sum of positive squares in 4 ways, for example, as 1229881 + 751689 = 1109^2 + 867^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3127 + ... + 3706.

2^1981570 is an apocalyptic number.

1981570 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1981570 is a deficient number, since it is larger than the sum of its proper divisors (1708790).

1981570 is a wasteful number, since it uses less digits than its factorization.

1981570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6869.

The product of its (nonzero) digits is 2520, while the sum is 31.

The square root of 1981570 is about 1407.6824926098. The cubic root of 1981570 is about 125.6039043643.

The spelling of 1981570 in words is "one million, nine hundred eighty-one thousand, five hundred seventy".