1221640734 has 16 divisors (see below), whose sum is σ = 2455686288. Its totient is φ = 405146112.

The previous prime is 1221640709. The next prime is 1221640759. The reversal of 1221640734 is 4370461221.

It is an interprime number because it is at equal distance from previous prime (1221640709) and next prime (1221640759).

It is a Curzon number.

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, 515587 + ... + 517950.

It is an arithmetic number, because the mean of its divisors is an integer number (153480393).

Almost surely, 2^1221640734 is an apocalyptic number.

1221640734 is an abundant number, since it is smaller than the sum of its proper divisors (1234045554).

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

1221640734 is a wasteful number, since it uses less digits than its factorization.

1221640734 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1033739.

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 1221640734 is about 34951.9775406199. The cubic root of 1221640734 is about 1069.0085246075.

The spelling of 1221640734 in words is "one billion, two hundred twenty-one million, six hundred forty thousand, seven hundred thirty-four".