1220631731 has 4 divisors (see below), whose sum is σ = 1331598264. Its totient is φ = 1109665200.

The previous prime is 1220631719. The next prime is 1220631733. The reversal of 1220631731 is 1371360221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1220631731 is a prime.

It is a super-2 number, since 2×1220631731² = 2979883645448112722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1220631731.

It is not an unprimeable number, because it can be changed into a prime (1220631733) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55483250 + ... + 55483271.

It is an arithmetic number, because the mean of its divisors is an integer number (332899566).

Almost surely, 2^1220631731 is an apocalyptic number.

1220631731 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1220631731 is a deficient number, since it is larger than the sum of its proper divisors (110966533).

1220631731 is a wasteful number, since it uses less digits than its factorization.

1220631731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110966532.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 1220631731 is about 34937.5404257369. The cubic root of 1220631731 is about 1068.7141309349.

Adding to 1220631731 its reverse (1371360221), we get a palindrome (2591991952).

The spelling of 1220631731 in words is "one billion, two hundred twenty million, six hundred thirty-one thousand, seven hundred thirty-one".