772221820 has 24 divisors (see below), whose sum is σ = 1665496224. Its totient is φ = 300540096.

The previous prime is 772221799. The next prime is 772221823. The reversal of 772221820 is 28122277.

It is a super-2 number, since 2×772221820² = 1192653078568224800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (772221823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 521032 + ... + 522511.

It is an arithmetic number, because the mean of its divisors is an integer number (69395676).

Almost surely, 2^772221820 is an apocalyptic number.

It is an amenable number.

772221820 is an abundant number, since it is smaller than the sum of its proper divisors (893274404).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

772221820 is a wasteful number, since it uses less digits than its factorization.

772221820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1043589 (or 1043587 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 772221820 is about 27788.8794304484. The cubic root of 772221820 is about 917.4463763031.

The spelling of 772221820 in words is "seven hundred seventy-two million, two hundred twenty-one thousand, eight hundred twenty".