1651221667 has 4 divisors (see below), whose sum is σ = 1651307080. Its totient is φ = 1651136256.

The previous prime is 1651221661. The next prime is 1651221683. The reversal of 1651221667 is 7661221561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1651221667 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1651221661) 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, 1648 + ... + 57490.

It is an arithmetic number, because the mean of its divisors is an integer number (412826770).

Almost surely, 2^1651221667 is an apocalyptic number.

1651221667 is a deficient number, since it is larger than the sum of its proper divisors (85413).

1651221667 is an equidigital number, since it uses as much as digits as its factorization.

1651221667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85412.

The product of its digits is 30240, while the sum is 37.

The square root of 1651221667 is about 40635.2269219701. The cubic root of 1651221667 is about 1181.9573152990.

The spelling of 1651221667 in words is "one billion, six hundred fifty-one million, two hundred twenty-one thousand, six hundred sixty-seven".