1621540667 has 2 divisors, whose sum is σ = 1621540668. Its totient is φ = 1621540666.

The previous prime is 1621540637. The next prime is 1621540681. The reversal of 1621540667 is 7660451261.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1621540667 - 2⁶ = 1621540603 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1621540667.

It is not a weakly prime, because it can be changed into another prime (1621540637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810770333 + 810770334.

It is an arithmetic number, because the mean of its divisors is an integer number (810770334).

Almost surely, 2^1621540667 is an apocalyptic number.

1621540667 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621540667 is an equidigital number, since it uses as much as digits as its factorization.

1621540667 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 38.

The square root of 1621540667 is about 40268.3581363830. The cubic root of 1621540667 is about 1174.8324896561.

The spelling of 1621540667 in words is "one billion, six hundred twenty-one million, five hundred forty thousand, six hundred sixty-seven".