1651891920 has 240 divisors, whose sum is σ = 6271295040. Its totient is φ = 357654528.

The previous prime is 1651891919. The next prime is 1651891931. The reversal of 1651891920 is 291981561.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×1651891920² = 5457493830722572800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 219744 + ... + 227136.

It is an arithmetic number, because the mean of its divisors is an integer number (26130396).

Almost surely, 2^1651891920 is an apocalyptic number.

1651891920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1651891920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3135647520).

1651891920 is an abundant number, since it is smaller than the sum of its proper divisors (4619403120).

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

1651891920 is a wasteful number, since it uses less digits than its factorization.

1651891920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7442 (or 7429 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 42.

The square root of 1651891920 is about 40643.4732767759. The cubic root of 1651891920 is about 1182.1172177693.

The spelling of 1651891920 in words is "one billion, six hundred fifty-one million, eight hundred ninety-one thousand, nine hundred twenty".