776561621 has 16 divisors (see below), whose sum is σ = 857158848. Its totient is φ = 697680000.

The previous prime is 776561603. The next prime is 776561647. The reversal of 776561621 is 126165677.

It is a cyclic number.

It is not a de Polignac number, because 776561621 - 2¹⁸ = 776299477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (776561221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 377231 + ... + 379283.

It is an arithmetic number, because the mean of its divisors is an integer number (53572428).

Almost surely, 2^776561621 is an apocalyptic number.

It is an amenable number.

776561621 is a deficient number, since it is larger than the sum of its proper divisors (80597227).

776561621 is a wasteful number, since it uses less digits than its factorization.

776561621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2452.

The product of its digits is 105840, while the sum is 41.

The square root of 776561621 is about 27866.8552405900. The cubic root of 776561621 is about 919.1618157463.

The spelling of 776561621 in words is "seven hundred seventy-six million, five hundred sixty-one thousand, six hundred twenty-one".