1261664 has 24 divisors (see below), whose sum is σ = 2517480. Its totient is φ = 622336.

The previous prime is 1261649. The next prime is 1261697. The reversal of 1261664 is 4661621.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2627 + ... + 3069.

It is an arithmetic number, because the mean of its divisors is an integer number (104895).

2^1261664 is an apocalyptic number.

It is an amenable number.

1261664 is a deficient number, since it is larger than the sum of its proper divisors (1255816).

1261664 is an equidigital number, since it uses as much as digits as its factorization.

1261664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 542 (or 534 counting only the distinct ones).

The product of its digits is 1728, while the sum is 26.

The square root of 1261664 is about 1123.2381759894. The cubic root of 1261664 is about 108.0557553904.

The spelling of 1261664 in words is "one million, two hundred sixty-one thousand, six hundred sixty-four".