1621742407766 has 16 divisors (see below), whose sum is σ = 2640365597184. Its totient is φ = 742602821184.

The previous prime is 1621742407759. The next prime is 1621742407799. The reversal of 1621742407766 is 6677042471261.

It is a super-2 number, since 2×1621742407766² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax 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, 245566415 + ... + 245573018.

It is an arithmetic number, because the mean of its divisors is an integer number (165022849824).

Almost surely, 2^{1621742407766} is an apocalyptic number.

1621742407766 is a deficient number, since it is larger than the sum of its proper divisors (1018623189418).

1621742407766 is a wasteful number, since it uses less digits than its factorization.

1621742407766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491139575.

The product of its (nonzero) digits is 4741632, while the sum is 53.

The spelling of 1621742407766 in words is "one trillion, six hundred twenty-one billion, seven hundred forty-two million, four hundred seven thousand, seven hundred sixty-six".