21661141620 has 48 divisors (see below), whose sum is σ = 62290424448. Its totient is φ = 5620187520.

The previous prime is 21661141543. The next prime is 21661141631. The reversal of 21661141620 is 2614116612.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4876416 + ... + 4880855.

It is an arithmetic number, because the mean of its divisors is an integer number (1297717176).

Almost surely, 2^21661141620 is an apocalyptic number.

21661141620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21661141620 is an abundant number, since it is smaller than the sum of its proper divisors (40629282828).

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

21661141620 is a wasteful number, since it uses less digits than its factorization.

21661141620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9757320 (or 9757318 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The spelling of 21661141620 in words is "twenty-one billion, six hundred sixty-one million, one hundred forty-one thousand, six hundred twenty".